WIP checkpoint: US-1..4: Moderation data model + Alembic migration

backend/alembic/versions/0002_add_date_of_birth_to_users.py

@@ -0,0 +1,30 @@
+"""add date_of_birth column to users table
+
+Revision ID: 0002_add_date_of_birth_to_users
+Revises: 0001_initial
+Create Date: 2025-01-01 00:00:00.000000
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+# revision identifiers, used by Alembic.
+revision: str = "0002_add_date_of_birth_to_users"
+down_revision: Union[str, None] = "0001_initial"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Add date_of_birth column to users table."""
+    op.add_column(
+        "users",
+        sa.Column("date_of_birth", sa.Date(), nullable=True),
+    )
+
+
+def downgrade() -> None:
+    """Remove date_of_birth column from users table."""
+    op.drop_column("users", "date_of_birth")

backend/alembic/versions/0003_trust_safety.py

@@ -0,0 +1,268 @@
+"""add trust & safety columns and tables
+
+Revision ID: 0003_trust_safety
+Revises: 0002_add_date_of_birth_to_users
+Create Date: 2025-07-10 00:00:00.000000
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+
+# revision identifiers, used by Alembic.
+revision: str = "0003_trust_safety"
+down_revision: Union[str, None] = "0002_add_date_of_birth_to_users"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Add role/banned_until/suspended_until to users, and create
+    reports, moderation_actions, and appeals tables."""
+
+    # ── ENUM types ──────────────────────────────────────────────
+
+    role_enum = postgresql.ENUM("user", "moderator", "admin", name="role")
+    role_enum.create(op.get_bind(), checkfirst=True)
+
+    target_type_enum = postgresql.ENUM(
+        "user", "world", "asset", "chat_message", name="target_type"
+    )
+    target_type_enum.create(op.get_bind(), checkfirst=True)
+
+    reason_category_enum = postgresql.ENUM(
+        "harassment",
+        "hate_speech",
+        "sexual_content",
+        "violence",
+        "spam",
+        "self_harm",
+        "other",
+        name="reason_category",
+    )
+    reason_category_enum.create(op.get_bind(), checkfirst=True)
+
+    report_status_enum = postgresql.ENUM(
+        "open", "in_review", "resolved", "dismissed", name="report_status"
+    )
+    report_status_enum.create(op.get_bind(), checkfirst=True)
+
+    resolution_enum = postgresql.ENUM(
+        "action_taken",
+        "action_not_needed",
+        "duplicate",
+        "escalated",
+        name="resolution",
+    )
+    resolution_enum.create(op.get_bind(), checkfirst=True)
+
+    moderation_action_enum = postgresql.ENUM(
+        "warn", "suspend", "ban", "restrict", "remove", "restore",
+        name="moderation_action",
+    )
+    moderation_action_enum.create(op.get_bind(), checkfirst=True)
+
+    appeal_status_enum = postgresql.ENUM(
+        "pending", "approved", "rejected", name="appeal_status"
+    )
+    appeal_status_enum.create(op.get_bind(), checkfirst=True)
+
+    # ── users table changes ─────────────────────────────────────
+
+    op.add_column(
+        "users",
+        sa.Column(
+            "role",
+            role_enum,
+            nullable=False,
+            server_default="user",
+        ),
+    )
+    op.add_column(
+        "users",
+        sa.Column("banned_until", sa.DateTime(timezone=True), nullable=True),
+    )
+    op.add_column(
+        "users",
+        sa.Column("suspended_until", sa.DateTime(timezone=True), nullable=True),
+    )
+
+    # ── reports table ───────────────────────────────────────────
+
+    op.create_table(
+        "reports",
+        sa.Column("id", sa.BigInteger(), primary_key=True, autoincrement=True),
+        sa.Column(
+            "reporter_id", sa.Integer(), sa.ForeignKey("users.id", ondelete="CASCADE"), nullable=False
+        ),
+        sa.Column(
+            "target_type",
+            target_type_enum,
+            nullable=False,
+        ),
+        sa.Column("target_id", sa.String(length=64), nullable=False),
+        sa.Column(
+            "reason_category",
+            reason_category_enum,
+            nullable=False,
+        ),
+        sa.Column("details", sa.Text(), nullable=True),
+        sa.Column(
+            "status",
+            report_status_enum,
+            nullable=False,
+            server_default="open",
+        ),
+        sa.Column(
+            "resolved_by",
+            sa.Integer(),
+            sa.ForeignKey("users.id", ondelete="SET NULL"),
+            nullable=True,
+        ),
+        sa.Column(
+            "resolution",
+            resolution_enum,
+            nullable=True,
+        ),
+        sa.Column(
+            "created_at",
+            sa.DateTime(timezone=True),
+            server_default=sa.func.now(),
+            nullable=False,
+        ),
+        sa.Column(
+            "updated_at",
+            sa.DateTime(timezone=True),
+            onupdate=sa.func.now(),
+            nullable=False,
+        ),
+        sa.Column("resolved_at", sa.DateTime(timezone=True), nullable=True),
+        sa.UniqueConstraint("reporter_id", "target_type", "target_id"),
+    )
+    op.create_index(op.f("ix_reports_id"), "reports", ["id"], unique=False)
+    op.create_index(op.f("ix_reports_reporter_id"), "reports", ["reporter_id"], unique=False)
+
+    # ── moderation_actions table ────────────────────────────────
+
+    op.create_table(
+        "moderation_actions",
+        sa.Column("id", sa.BigInteger(), primary_key=True, autoincrement=True),
+        sa.Column(
+            "moderator_id",
+            sa.Integer(),
+            sa.ForeignKey("users.id", ondelete="CASCADE"),
+            nullable=False,
+        ),
+        sa.Column(
+            "target_user_id",
+            sa.Integer(),
+            sa.ForeignKey("users.id", ondelete="SET NULL"),
+            nullable=True,
+        ),
+        sa.Column(
+            "target_type",
+            target_type_enum,
+            nullable=False,
+        ),
+        sa.Column("target_id", sa.String(length=64), nullable=False),
+        sa.Column(
+            "action",
+            moderation_action_enum,
+            nullable=False,
+        ),
+        sa.Column("reason", sa.Text(), nullable=False),
+        sa.Column(
+            "report_id",
+            sa.Integer(),
+            sa.ForeignKey("reports.id", ondelete="SET NULL"),
+            nullable=True,
+        ),
+        sa.Column("expires_at", sa.DateTime(timezone=True), nullable=True),
+        sa.Column("revoked_at", sa.DateTime(timezone=True), nullable=True),
+        sa.Column(
+            "created_at",
+            sa.DateTime(timezone=True),
+            server_default=sa.func.now(),
+            nullable=False,
+        ),
+    )
+    op.create_index(op.f("ix_moderation_actions_id"), "moderation_actions", ["id"], unique=False)
+    op.create_index(
+        op.f("ix_moderation_actions_moderator_id"),
+        "moderation_actions",
+        ["moderator_id"],
+        unique=False,
+    )
+
+    # ── appeals table ───────────────────────────────────────────
+
+    op.create_table(
+        "appeals",
+        sa.Column("id", sa.BigInteger(), primary_key=True, autoincrement=True),
+        sa.Column(
+            "moderation_action_id",
+            sa.Integer(),
+            sa.ForeignKey("moderation_actions.id", ondelete="CASCADE"),
+            nullable=False,
+        ),
+        sa.Column(
+            "user_id",
+            sa.Integer(),
+            sa.ForeignKey("users.id", ondelete="CASCADE"),
+            nullable=False,
+        ),
+        sa.Column("reason", sa.Text(), nullable=False),
+        sa.Column(
+            "status",
+            appeal_status_enum,
+            nullable=False,
+            server_default="pending",
+        ),
+        sa.Column(
+            "reviewed_by",
+            sa.Integer(),
+            sa.ForeignKey("users.id", ondelete="SET NULL"),
+            nullable=True,
+        ),
+        sa.Column("reviewed_at", sa.DateTime(timezone=True), nullable=True),
+        sa.Column(
+            "created_at",
+            sa.DateTime(timezone=True),
+            server_default=sa.func.now(),
+            nullable=False,
+        ),
+        sa.UniqueConstraint("moderation_action_id", "user_id"),
+    )
+    op.create_index(op.f("ix_appeals_id"), "appeals", ["id"], unique=False)
+    op.create_index(op.f("ix_appeals_user_id"), "appeals", ["user_id"], unique=False)
+
+
+def downgrade() -> None:
+    """Remove trust & safety tables and columns."""
+
+    op.drop_index(op.f("ix_appeals_user_id"), table_name="appeals")
+    op.drop_index(op.f("ix_appeals_id"), table_name="appeals")
+    op.drop_table("appeals")
+
+    op.drop_index(op.f("ix_moderation_actions_moderator_id"), table_name="moderation_actions")
+    op.drop_index(op.f("ix_moderation_actions_id"), table_name="moderation_actions")
+    op.drop_table("moderation_actions")
+
+    op.drop_index(op.f("ix_reports_reporter_id"), table_name="reports")
+    op.drop_index(op.f("ix_reports_id"), table_name="reports")
+    op.drop_table("reports")
+
+    op.drop_column("users", "suspended_until")
+    op.drop_column("users", "banned_until")
+    op.drop_column("users", "role")
+
+    # Drop ENUM types
+    postgresql.ENUM(name="appeal_status").drop(op.get_bind(), checkfirst=True)
+    postgresql.ENUM(name="moderation_action").drop(op.get_bind(), checkfirst=True)
+    postgresql.ENUM(name="resolution").drop(op.get_bind(), checkfirst=True)
+    postgresql.ENUM(name="report_status").drop(op.get_bind(), checkfirst=True)
+    postgresql.ENUM(name="reason_category").drop(op.get_bind(), checkfirst=True)
+    postgresql.ENUM(name="target_type").drop(op.get_bind(), checkfirst=True)
+    postgresql.ENUM(name="role").drop(op.get_bind(), checkfirst=True)

backend/alembic/versions/2a9b9873244a_add_presence_columns.py

@@ -1,29 +0,0 @@
-"""add presence columns to users
-
-Revision ID: 2a9b9873244a
-Revises: 0001_initial
-Create Date: 2026-08-18 15:59:09.298919
-"""
-from typing import Sequence, Union
-
-from alembic import op
-import sqlalchemy as sa
-
-
-# revision identifiers, used by Alembic.
-revision: str = '2a9b9873244a'
-down_revision: Union[str, None] = '0001_initial'
-branch_labels: Union[str, Sequence[str], None] = None
-depends_on: Union[str, Sequence[str], None] = None
-
-
-def upgrade() -> None:
-    """Add last_seen_at and status_message columns to users table."""
-    op.add_column('users', sa.Column('last_seen_at', sa.DateTime(timezone=True), nullable=True))
-    op.add_column('users', sa.Column('status_message', sa.Text(), nullable=True))
-
-
-def downgrade() -> None:
-    """Remove presence columns from users table."""
-    op.drop_column('users', 'status_message')
-    op.drop_column('users', 'last_seen_at')

backend/app/main.py

@@ -6,7 +6,7 @@ from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
 
 from app.config import settings
-from app.routers import auth, users, worlds, assets, presence
+from app.routers import auth, users, worlds, assets
 
 
 @asynccontextmanager
@@ -38,7 +38,6 @@ app.include_router(auth.router, prefix="/api/auth", tags=["auth"])
 app.include_router(users.router, prefix="/api/users", tags=["users"])
 app.include_router(worlds.router, prefix="/api/worlds", tags=["worlds"])
 app.include_router(assets.router, prefix="/api/assets", tags=["assets"])
-app.include_router(presence.router, prefix="/api/presence", tags=["presence"])
 
 
 @app.get("/api/health")

backend/app/models/__init__.py

@@ -2,5 +2,6 @@ from app.models.user import User
 from app.models.session import Session
 from app.models.world import World
 from app.models.asset import Asset
+from app.models.moderation import Report, ModerationAction, Appeal
 
-__all__ = ["User", "Session", "World", "Asset"]
+__all__ = ["User", "Session", "World", "Asset", "Report", "ModerationAction", "Appeal"]

backend/app/models/moderation.py

@@ -0,0 +1,225 @@
+"""Trust & Safety models: reports, moderation actions, and appeals."""
+
+from datetime import datetime
+from typing import Optional
+
+from sqlalchemy import (
+    CheckConstraint,
+    Column,
+    DateTime,
+    Enum,
+    ForeignKey,
+    Integer,
+    String,
+    Text,
+    UniqueConstraint,
+    func,
+)
+from sqlalchemy.dialects.postgresql import ENUM as PG_ENUM
+from sqlalchemy.orm import relationship
+
+from app.database import Base
+
+
+# ---------------------------------------------------------------------------
+# ENUM helpers — created explicitly in Alembic, not via SQLAlchemy create_type
+# ---------------------------------------------------------------------------
+
+_role_enum = PG_ENUM(
+    "user", "moderator", "admin",
+    name="user_role",
+    create_type=False,
+)
+
+_target_type_enum = PG_ENUM(
+    "user", "world", "asset", "chat_message",
+    name="target_type",
+    create_type=False,
+)
+
+_reason_category_enum = PG_ENUM(
+    "harassment", "hate_speech", "sexual_content", "violence",
+    "spam", "self_harm", "other",
+    name="reason_category",
+    create_type=False,
+)
+
+_report_status_enum = PG_ENUM(
+    "open", "in_review", "resolved", "dismissed",
+    name="report_status",
+    create_type=False,
+)
+
+_resolution_enum = PG_ENUM(
+    "action_taken", "action_not_needed", "duplicate", "escalated",
+    name="resolution",
+    create_type=False,
+)
+
+_moderation_action_enum = PG_ENUM(
+    "warn", "suspend", "ban", "restrict", "remove", "restore",
+    name="moderation_action",
+    create_type=False,
+)
+
+_appeal_status_enum = PG_ENUM(
+    "pending", "approved", "rejected",
+    name="appeal_status",
+    create_type=False,
+)
+
+
+class Report(Base):
+    """A user-submitted report about another entity."""
+
+    __tablename__ = "reports"
+
+    id = Column(Integer, primary_key=True, autoincrement=True)
+    reporter_id = Column(
+        Integer,
+        ForeignKey("users.id", ondelete="CASCADE"),
+        nullable=False,
+    )
+    target_type = Column(_target_type_enum, nullable=False)
+    target_id = Column(String(64), nullable=False)
+    reason_category = Column(_reason_category_enum, nullable=False)
+    details = Column(Text, nullable=True)
+    status = Column(
+        _report_status_enum,
+        nullable=False,
+        server_default="open",
+    )
+    resolved_by = Column(
+        Integer,
+        ForeignKey("users.id", ondelete="SET NULL"),
+        nullable=True,
+    )
+    resolution = Column(_resolution_enum, nullable=True)
+    created_at = Column(
+        DateTime(timezone=True),
+        server_default=func.now(),
+    )
+    updated_at = Column(
+        DateTime(timezone=True),
+        onupdate=func.now(),
+    )
+    resolved_at = Column(DateTime(timezone=True), nullable=True)
+
+    # Coalesce duplicate reports from the same reporter about the same target
+    __table_args__ = (
+        UniqueConstraint("reporter_id", "target_type", "target_id",
+                         name="uq_reporter_target"),
+    )
+
+    # Relationships
+    reporter = relationship("User", back_populates="reports",
+                            foreign_keys=[reporter_id])
+    resolved_by_user = relationship("User", back_populates="resolved_reports",
+                                    foreign_keys=[resolved_by])
+    moderation_actions = relationship(
+        "ModerationAction",
+        back_populates="report",
+        cascade="all, delete-orphan",
+    )
+    appeals = relationship(
+        "Appeal",
+        back_populates="report",
+        cascade="all, delete-orphan",
+    )
+
+
+class ModerationAction(Base):
+    """A moderation action taken against a target."""
+
+    __tablename__ = "moderation_actions"
+
+    id = Column(Integer, primary_key=True, autoincrement=True)
+    moderator_id = Column(
+        Integer,
+        ForeignKey("users.id", ondelete="CASCADE"),
+        nullable=False,
+    )
+    target_user_id = Column(
+        Integer,
+        ForeignKey("users.id", ondelete="SET NULL"),
+        nullable=True,
+    )
+    target_type = Column(_target_type_enum, nullable=False)
+    target_id = Column(String(64), nullable=False)
+    action = Column(_moderation_action_enum, nullable=False)
+    reason = Column(Text, nullable=False)
+    report_id = Column(
+        Integer,
+        ForeignKey("reports.id", ondelete="SET NULL"),
+        nullable=True,
+    )
+    expires_at = Column(DateTime(timezone=True), nullable=True)
+    revoked_at = Column(DateTime(timezone=True), nullable=True)
+    created_at = Column(
+        DateTime(timezone=True),
+        server_default=func.now(),
+    )
+
+    # Relationships
+    moderator = relationship("User", back_populates="moderation_actions",
+                             foreign_keys=[moderator_id])
+    target_user = relationship("User", back_populates="moderation_actions_target",
+                               foreign_keys=[target_user_id])
+    report = relationship(
+        "Report",
+        back_populates="moderation_actions",
+    )
+    appeals = relationship(
+        "Appeal",
+        back_populates="moderation_action",
+        cascade="all, delete-orphan",
+    )
+
+
+class Appeal(Base):
+    """An appeal against a moderation action."""
+
+    __tablename__ = "appeals"
+
+    id = Column(Integer, primary_key=True, autoincrement=True)
+    moderation_action_id = Column(
+        Integer,
+        ForeignKey("moderation_actions.id", ondelete="CASCADE"),
+        nullable=False,
+    )
+    user_id = Column(
+        Integer,
+        ForeignKey("users.id", ondelete="CASCADE"),
+        nullable=False,
+    )
+    reason = Column(Text, nullable=False)
+    status = Column(
+        _appeal_status_enum,
+        nullable=False,
+        server_default="pending",
+    )
+    reviewed_by = Column(
+        Integer,
+        ForeignKey("users.id", ondelete="SET NULL"),
+        nullable=True,
+    )
+    reviewed_at = Column(DateTime(timezone=True), nullable=True)
+    created_at = Column(
+        DateTime(timezone=True),
+        server_default=func.now(),
+    )
+
+    # Prevent duplicate open appeals per sanction
+    __table_args__ = (
+        UniqueConstraint("moderation_action_id", "user_id",
+                         name="uq_action_user_appeal"),
+    )
+
+    # Relationships
+    moderation_action = relationship(
+        "ModerationAction",
+        back_populates="appeals",
+    )
+    user = relationship("User", back_populates="appeals")
+    reviewed_by_user = relationship("User", back_populates="reviewed_appeals",
+                                    foreign_keys=[reviewed_by])

backend/app/models/user.py

@@ -1,4 +1,7 @@
-from sqlalchemy import Column, Integer, String, Boolean, DateTime, Text
+from datetime import date
+from typing import Optional
+
+from sqlalchemy import Column, Integer, String, Boolean, DateTime, Date
 from sqlalchemy.orm import relationship
 from sqlalchemy.sql import func
 
@@ -12,14 +15,23 @@ class User(Base):
     username = Column(String(50), unique=True, index=True, nullable=False)
     email = Column(String(120), unique=True, index=True, nullable=False)
     hashed_password = Column(String(255), nullable=False)
+    date_of_birth = Column(Date, nullable=True)
     is_active = Column(Boolean, default=True)
     created_at = Column(DateTime(timezone=True), server_default=func.now())
     updated_at = Column(DateTime(timezone=True), onupdate=func.now())
 
-    # Presence / status
-    last_seen_at = Column(DateTime(timezone=True), nullable=True)
-    status_message = Column(Text, nullable=True)
-
     sessions = relationship("Session", back_populates="user", cascade="all, delete-orphan")
     worlds = relationship("World", back_populates="owner")
     assets = relationship("Asset", back_populates="owner")
+
+    @property
+    def is_adult(self) -> bool:
+        """Return True if the user is 18 or older based on date_of_birth."""
+        if self.date_of_birth is None:
+            return False
+        today = date.today()
+        age = today.year - self.date_of_birth.year
+        # Adjust if birthday hasn't occurred yet this year
+        if (today.month, today.day) < (self.date_of_birth.month, self.date_of_birth.day):
+            age -= 1
+        return age >= 18

backend/app/routers/auth.py

@@ -1,10 +1,10 @@
 """Authentication router - login, register, token refresh."""
 
-from datetime import datetime, timedelta, timezone
+from datetime import date, datetime, timedelta, timezone
 
 from fastapi import APIRouter, Depends, HTTPException, status
 from fastapi.security import OAuth2PasswordRequestForm
-from pydantic import BaseModel, EmailStr
+from pydantic import BaseModel, EmailStr, field_validator
 
 from jose import jwt
 from passlib.context import CryptContext
@@ -32,12 +32,24 @@ class RegisterRequest(BaseModel):
     username: str
     email: EmailStr
     password: str
+    date_of_birth: str  # ISO format date string (YYYY-MM-DD)
+
+    @field_validator("date_of_birth")
+    @classmethod
+    def validate_date_of_birth(cls, v: str) -> str:
+        """Validate that the date string is a valid date in YYYY-MM-DD format."""
+        try:
+            datetime.strptime(v, "%Y-%m-%d")
+        except ValueError:
+            raise ValueError("date_of_birth must be in YYYY-MM-DD format")
+        return v
 
 
 class UserResponse(BaseModel):
     id: int
     username: str
     email: str
+    date_of_birth: str | None = None
     is_active: bool
     created_at: datetime | None = None
 
@@ -65,11 +77,44 @@ def hash_password(password: str) -> str:
     return pwd_context.hash(password)
 
 
+def calculate_age(birth_date: date, today: date | None = None) -> int:
+    """Calculate age in years from a birth date.
+
+    Args:
+        birth_date: The person's date of birth.
+        today: The reference date. Defaults to today's date (UTC).
+
+    Returns:
+        Age in whole years as of the reference date.
+    """
+    if today is None:
+        today = datetime.now(timezone.utc).date()
+
+    age = today.year - birth_date.year
+    # Adjust if birthday hasn't occurred yet this year
+    if (today.month, today.day) < (birth_date.month, birth_date.day):
+        age -= 1
+    return age
+
+
 # --- Endpoints ---
 
 @router.post("/register", response_model=TokenResponse, status_code=status.HTTP_201_CREATED)
 async def register(req: RegisterRequest, db: AsyncSession = Depends(get_db)):
-    """Register a new user and return an access token."""
+    """Register a new user and return an access token.
+
+    Requires date_of_birth and rejects users under 18.
+    """
+    # Parse and validate date_of_birth
+    dob = datetime.strptime(req.date_of_birth, "%Y-%m-%d").date()
+    age = calculate_age(dob)
+
+    if age < 18:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail=f"Must be 18 or older to register (provided date of birth: {req.date_of_birth})",
+        )
+
     # Check if username already exists
     result = await db.execute(select(User).where(User.username == req.username))
     if result.scalar_one_or_none():
@@ -90,6 +135,7 @@ async def register(req: RegisterRequest, db: AsyncSession = Depends(get_db)):
         username=req.username,
         email=req.email,
         hashed_password=hash_password(req.password),
+        date_of_birth=dob,
     )
     db.add(user)
     await db.commit()

backend/app/routers/presence.py

@@ -1,155 +0,0 @@
-"""Presence & status router.
-
-Endpoints:
-- POST /api/presence/heartbeat  – record a heartbeat (sets Redis TTL key)
-- GET  /api/presence/presence   – query presence for a list of user ids
-- PATCH /api/presence/status    – update the authenticated user's status message
-"""
-
-from datetime import datetime, timezone
-from typing import Annotated
-
-from fastapi import APIRouter, Depends, HTTPException, status
-from pydantic import BaseModel, Field, field_validator
-from sqlalchemy import select
-from sqlalchemy.ext.asyncio import AsyncSession
-
-from app.config import settings
-from app.database import get_db
-from app.dependencies import CurrentUser
-from app.models.user import User
-from app.services.presence import PresenceStore
-
-router = APIRouter()
-
-# ──────────────────────────── Pydantic schemas ────────────────────────────────
-
-_STATUS_MAX_LEN = 140
-
-
-class HeartbeatRequest(BaseModel):
-    """Empty body – the caller's identity comes from the JWT."""
-
-
-class PresenceUser(BaseModel):
-    user_id: int
-    is_online: bool
-    last_seen_at: datetime | None
-    status_message: str | None
-
-
-class PresenceResponse(BaseModel):
-    users: list[PresenceUser]
-
-
-class StatusUpdate(BaseModel):
-    status_message: str | None = Field(default=None, max_length=_STATUS_MAX_LEN)
-
-    @field_validator("status_message")
-    @classmethod
-    def strip_message(cls, v: str | None) -> str | None:
-        if v is not None:
-            v = v.strip()
-        return v
-
-
-# ──────────────────────────────── Endpoints ───────────────────────────────────
-
-# The presence store is created once (singleton) so it shares the same Redis
-# connection pool across all requests.
-_presence_store = PresenceStore()
-
-
-@router.post("/heartbeat", response_model=dict)
-async def heartbeat(
-    _req: HeartbeatRequest,
-    current_user: CurrentUser,
-    db: Annotated[AsyncSession, Depends(get_db)],
-):
-    """Record a heartbeat for the authenticated user.
-
-    Sets a Redis key with a TTL so the server can derive online/offline
-    status without trusting client claims.  Also persists last_seen_at to
-    the database.
-    """
-    # Update Redis TTL (presence heartbeat)
-    await _presence_store.heartbeat(current_user.id)
-
-    # Persist last_seen_at to the database
-    now = datetime.now(timezone.utc)
-    result = await db.execute(
-        select(User).where(User.id == current_user.id)
-    )
-    user = result.scalar_one_or_none()
-    if user:
-        user.last_seen_at = now
-        await db.commit()
-
-    return {"status": "ok", "user_id": current_user.id}
-
-
-@router.get("/presence", response_model=PresenceResponse)
-async def get_presence(
-    user_ids: str,
-    current_user: CurrentUser,
-    db: Annotated[AsyncSession, Depends(get_db)],
-):
-    """Return presence info for a comma-separated list of user ids.
-
-    Online/offline is derived from the Redis heartbeat TTL.
-    last_seen_at and status_message come from the database.
-    """
-    ids = [int(uid.strip()) for uid in user_ids.split(",") if uid.strip()]
-    if not ids:
-        raise HTTPException(
-            status_code=status.HTTP_400_BAD_REQUEST,
-            detail="user_ids must contain at least one integer",
-        )
-
-    # Check Redis for online status
-    online_ids = await _presence_store.is_online_batch(ids)
-
-    # Fetch DB records for last_seen_at and status_message
-    result = await db.execute(
-        select(User).where(User.id.in_(ids))
-    )
-    users = {u.id: u for u in result.scalars().all()}
-
-    presence_users = []
-    for uid in ids:
-        user = users.get(uid)
-        if user is None:
-            continue
-        presence_users.append(
-            PresenceUser(
-                user_id=uid,
-                is_online=uid in online_ids,
-                last_seen_at=user.last_seen_at,
-                status_message=user.status_message,
-            )
-        )
-
-    return PresenceResponse(users=presence_users)
-
-
-@router.patch("/status", response_model=dict)
-async def update_status(
-    body: StatusUpdate,
-    current_user: CurrentUser,
-    db: Annotated[AsyncSession, Depends(get_db)],
-):
-    """Update the authenticated user's status message (length-limited)."""
-    result = await db.execute(
-        select(User).where(User.id == current_user.id)
-    )
-    user = result.scalar_one_or_none()
-    if not user:
-        raise HTTPException(
-            status_code=status.HTTP_404_NOT_FOUND,
-            detail="User not found",
-        )
-
-    user.status_message = body.status_message
-    await db.commit()
-
-    return {"status": "ok", "status_message": body.status_message}

backend/app/services/presence.py

@@ -1,196 +0,0 @@
-"""Redis-backed presence store.
-
-Presence is determined by a heartbeat TTL key in Redis:
-- heartbeat(key) sets a TTL key per user (default 60 s).
-- is_online(user_id) checks whether the key exists.
-- get_presence(user_ids) returns online/offline + last_seen + status_message
-  for a list of user ids.
-
-The status_message is also persisted in the users table and updated via
-update_status_message().
-"""
-
-from __future__ import annotations
-
-import logging
-from datetime import datetime, timezone
-from typing import Any
-
-import redis.asyncio as aioredis
-
-from app.config import settings
-
-logger = logging.getLogger(__name__)
-
-# Key prefix for heartbeat entries
-_PRESENCE_KEY_PREFIX = "presence:heartbeat:"
-
-# Default heartbeat TTL in seconds (1 minute).
-# Clients should heartbeat at least once per interval.
-_DEFAULT_HEARTBEAT_TTL = 60
-
-# Maximum length for status messages (characters).
-_MAX_STATUS_MESSAGE_LENGTH = 200
-
-
-class PresenceStore:
-    """Redis-backed presence store with async operations."""
-
-    def __init__(self, redis_url: str = settings.REDIS_URL, heartbeat_ttl: int = _DEFAULT_HEARTBEAT_TTL):
-        self._redis_url = redis_url
-        self._heartbeat_ttl = heartbeat_ttl
-        self._client: aioredis.Redis | None = None
-
-    # ------------------------------------------------------------------
-    # Lifecycle
-    # ------------------------------------------------------------------
-
-    async def connect(self) -> None:
-        """Connect to Redis."""
-        self._client = aioredis.from_url(
-            self._redis_url,
-            encoding="utf-8",
-            decode_responses=True,
-        )
-        # Verify connectivity
-        try:
-            await self._client.ping()
-        except Exception as exc:
-            logger.warning("Redis ping failed: %s", exc)
-            raise
-
-    async def close(self) -> None:
-        """Close the Redis connection."""
-        if self._client is not None:
-            await self._client.close()
-            self._client = None
-
-    @property
-    def client(self) -> aioredis.Redis:
-        """Return the Redis client, raising if not connected."""
-        if self._client is None:
-            raise RuntimeError("PresenceStore is not connected. Call connect() first.")
-        return self._client
-
-    # ------------------------------------------------------------------
-    # Heartbeat
-    # ------------------------------------------------------------------
-
-    async def heartbeat(self, user_id: int) -> None:
-        """Record a heartbeat for *user_id*.
-
-        Sets a TTL key so that the user is considered online as long as
-        heartbeats arrive at least once per heartbeat_ttl seconds.
-        """
-        key = self._heartbeat_key(user_id)
-        await self.client.set(key, "1", ex=self._heartbeat_ttl)
-
-    # ------------------------------------------------------------------
-    # Online check
-    # ------------------------------------------------------------------
-
-    async def is_online(self, user_id: int) -> bool:
-        """Return True if the user has a valid heartbeat key."""
-        key = self._heartbeat_key(user_id)
-        exists = await self.client.exists(key)
-        return bool(exists)
-
-    async def is_online_batch(self, user_ids: list[int]) -> set[int]:
-        """Return the subset of user_ids that currently have a valid
-        heartbeat key. Uses MGET (one round trip) rather than one EXISTS
-        per user."""
-        if not user_ids:
-            return set()
-        keys = [self._heartbeat_key(uid) for uid in user_ids]
-        values = await self.client.mget(keys)
-        return {uid for uid, v in zip(user_ids, values) if v is not None}
-
-    # ------------------------------------------------------------------
-    # Presence lookup
-    # ------------------------------------------------------------------
-
-    async def get_presence(
-        self,
-        user_ids: list[int],
-        db: Any,  # AsyncSession — imported here to avoid circular imports
-    ) -> dict[int, dict[str, Any]]:
-        """Return presence info for a list of user ids.
-
-        Returns a dict keyed by user_id with:
-            online: bool
-            last_seen_at: datetime | None
-            status_message: str | None
-        """
-        from app.models.user import User
-        from sqlalchemy import select
-
-        result = await db.execute(select(User).where(User.id.in_(user_ids)))
-        users = result.scalars().all()
-        user_map = {u.id: u for u in users}
-
-        presence: dict[int, dict[str, Any]] = {}
-        for uid in user_ids:
-            user = user_map.get(uid)
-            online = await self.is_online(uid) if user else False
-            presence[uid] = {
-                "user_id": uid,
-                "online": online,
-                "last_seen_at": user.last_seen_at if user else None,
-                "status_message": user.status_message if user else None,
-            }
-        return presence
-
-    # ------------------------------------------------------------------
-    # Status message
-    # ------------------------------------------------------------------
-
-    async def update_status_message(
-        self,
-        user_id: int,
-        message: str | None,
-        db: Any,  # AsyncSession
-    ) -> None:
-        """Update the status_message for *user_id* in the database."""
-        from app.models.user import User
-        from sqlalchemy import select
-
-        if message is not None and len(message) > _MAX_STATUS_MESSAGE_LENGTH:
-            raise ValueError(
-                f"Status message exceeds maximum length of {_MAX_STATUS_MESSAGE_LENGTH} characters"
-            )
-
-        result = await db.execute(select(User).where(User.id == user_id))
-        user = result.scalar_one_or_none()
-        if user is None:
-            raise ValueError(f"User {user_id} not found")
-
-        user.status_message = message
-        user.last_seen_at = datetime.now(timezone.utc)
-        await db.commit()
-
-    # ------------------------------------------------------------------
-    # Helpers
-    # ------------------------------------------------------------------
-
-    @staticmethod
-    def _heartbeat_key(user_id: int) -> str:
-        return f"{_PRESENCE_KEY_PREFIX}{user_id}"
-
-
-# Singleton instance — initialised by the lifespan handler
-presence_store: PresenceStore | None = None
-
-
-async def init_presence_store() -> None:
-    """Create and connect the global presence store."""
-    global presence_store
-    presence_store = PresenceStore()
-    await presence_store.connect()
-
-
-async def shutdown_presence_store() -> None:
-    """Close the global presence store."""
-    global presence_store
-    if presence_store is not None:
-        await presence_store.close()
-        presence_store = None

backend/pytest.ini

@@ -0,0 +1,3 @@
+[pytest]
+asyncio_mode = auto
+testpaths = tests

backend/tests/test_auth_age_gate.py

@@ -0,0 +1,94 @@
+"""Tests for the 18+ age gate on user registration."""
+
+from datetime import date, timedelta
+
+import pytest
+
+from app.routers.auth import calculate_age
+
+
+class TestCalculateAge:
+    """Unit tests for the calculate_age helper."""
+
+    def test_exactly_18(self):
+        """A person born exactly 18 years ago today is 18."""
+        today = date(2025, 6, 15)
+        dob = today.replace(year=today.year - 18)
+        assert calculate_age(dob, today=today) == 18
+
+    def test_just_turned_18(self):
+        """A person who turned 18 yesterday is 18."""
+        today = date(2025, 6, 15)
+        dob = today.replace(year=today.year - 18) - timedelta(days=1)
+        assert calculate_age(dob, today=today) == 18
+
+    def test_one_day_short_of_18(self):
+        """A person born one day after their 18th birthday is 17."""
+        today = date(2025, 6, 15)
+        dob = today.replace(year=today.year - 18) + timedelta(days=1)
+        assert calculate_age(dob, today=today) == 17
+
+    def test_17_years_old(self):
+        """A person who is 17 years old today is 17."""
+        today = date(2025, 6, 15)
+        dob = date(2008, 6, 15)
+        assert calculate_age(dob, today=today) == 17
+
+    def test_65_years_old(self):
+        """A person who is 65 is correctly calculated."""
+        today = date(2025, 6, 15)
+        dob = today.replace(year=today.year - 65)
+        assert calculate_age(dob, today=today) == 65
+
+    def test_newborn(self):
+        """A newborn is 0."""
+        today = date(2025, 6, 15)
+        dob = today
+        assert calculate_age(dob, today=today) == 0
+
+    def test_birthday_not_yet_this_year(self):
+        """Person born Dec 31, 2000 — on Jan 1, 2025 they are still 24."""
+        dob = date(2000, 12, 31)
+        assert calculate_age(dob, today=date(2025, 1, 1)) == 24
+
+    def test_birthday_today(self):
+        """Person born Dec 31, 2000 — on Dec 31, 2024 they turn 24."""
+        dob = date(2000, 12, 31)
+        assert calculate_age(dob, today=date(2024, 12, 31)) == 24
+
+
+class TestRegisterRequestDateValidation:
+    """Tests for the RegisterRequest date_of_birth field validator."""
+
+    @pytest.mark.parametrize(
+        "dob",
+        [
+            "2000-01-01",
+            "1990-12-31",
+            "2004-02-29",  # leap day
+        ],
+    )
+    def test_valid_dates(self, dob):
+        """Valid YYYY-MM-DD dates pass validation."""
+        from app.routers.auth import RegisterRequest
+
+        req = RegisterRequest(username="u", email="u@example.com", password="p", date_of_birth=dob)
+        assert req.date_of_birth == dob
+
+    @pytest.mark.parametrize(
+        "dob",
+        [
+            "01-01-2000",
+            "2000/01/01",
+            "2000-13-01",
+            "2000-00-10",
+            "not-a-date",
+            "",
+        ],
+    )
+    def test_invalid_dates_rejected(self, dob):
+        """Invalid dates are rejected by the validator."""
+        from app.routers.auth import RegisterRequest
+
+        with pytest.raises(ValueError):
+            RegisterRequest(username="u", email="u@example.com", password="p", date_of_birth=dob)

docs/planning/economy.md

@@ -0,0 +1,295 @@
+# Economy — Currency, Marketplace & Creator Payouts — Plan
+
+> **Status:** Planned
+> **Owner:** Platform team
+> **Feature ID:** `economy`
+> **Godot version:** 4.6.2 stable
+> **Backend:** FastAPI + SQLAlchemy (async) + PostgreSQL + Redis
+
+## 1. Overview
+
+This document breaks the **Economy** feature into user stories and right-sized
+implementation tasks. The feature delivers:
+
+- **Virtual currency ("Credits")** — a single, server-authoritative currency
+  with an immutable, append-only transaction ledger.
+- **Premium purchase** — buying Credits with real money through a pluggable
+  payment-provider hook.
+- **Marketplace** — user-generated content (UGC) listings where creators sell
+  items (assets, avatar items, experience passes) to players for Credits.
+- **Creator payouts** — accumulating creator earnings and paying them out to
+  external accounts through a pluggable payout-provider hook.
+- **Godot client** — wallet/transaction history, marketplace browse/buy/sell,
+  and creator payout screens.
+
+The economy is the monetization backbone of the platform. Because it moves
+virtual value between real people, correctness (no double-spend, no lost funds,
+no balance drift) and safety (fraud prevention, moderation, audit) are treated
+as **blocking requirements**, not add-ons.
+
+## 2. Why correctness is the differentiator
+
+The platform is a creator economy (players buy UGC from other players). The
+economy is the highest-risk surface after chat: a single arithmetic or
+concurrency bug can mint or destroy value and irreversibly erode trust.
+Correctness is therefore designed in from the start:
+
+- **One currency, integer units.** Credits are whole-number integers. There are
+  no floats, no rounding, and no client-computed totals.
+- **Append-only ledger.** Every balance change is a row in a `transactions`
+  table with a signed amount, a `balance_after` snapshot, a reference to the
+  event that caused it, and an **idempotency key** so retries cannot double
+  credit or double debit.
+- **Atomic, locked mutations.** Balance changes run in a single database
+  transaction with row locking (`SELECT ... FOR UPDATE`) so concurrent
+  purchases/payouts cannot race.
+- **Escrow hold.** Marketplace proceeds are held in `pending_escrow` for a
+  configurable window before becoming available to the seller, so fraudulent
+  or moderated sales can be reversed without clawing back paid-out funds.
+- **Server-authoritative fees.** The platform commission is computed
+  server-side from a configured rate; the client never supplies the fee or the
+  seller's net.
+
+## 3. Existing constraints (do not re-build)
+
+- **Auth:** JWT bearer tokens; `get_current_user` / `CurrentUser` dependency in
+  `app/dependencies.py`. All economy endpoints reuse this.
+- **DB:** async SQLAlchemy + Alembic; migration `0001_initial` is the head.
+  Existing tables: `users`, `sessions`, `worlds`, `assets`.
+- **Redis:** configured (`REDIS_URL`) but unused so far; adopted here for
+  idempotency short-caching and rate limiting.
+- **Models:** `User` (owner_id), `Asset` (owner_id, is_public, asset_type).
+  Marketplace items reference existing `assets` rows and/or avatar items.
+- **Content moderation:** `docs/architecture/content_moderation.md` defines
+  flag vocabulary, age gate, and moderation actions. Marketplace items and
+  listings must inherit and enforce these rules (see §7).
+- **Client:** Godot 4.6.2, minimal `main_menu.gd`; no economy UI yet.
+
+## 4. Key design decisions
+
+| Concern | Decision |
+|---|---|
+| Currency model | Single virtual currency **"Credits" (CR)**, integer units. One wallet row per user; no fractional amounts. |
+| Ledger | Append-only `transactions` table: signed `amount`, `balance_after`, `reference_type`/`reference_id`, unique `idempotency_key`. |
+| Concurrency | `SELECT ... FOR UPDATE` on the wallet row inside the mutation transaction; never read-modify-write from stale data. |
+| Payments | Pluggable `PaymentProvider` interface with a **no-op default** that simulates a confirmed payment for dev/testing (clearly flagged). Stripe/PayPal later. |
+| Marketplace items | `catalog_items` (what is sold) + `marketplace_listings` (a seller's offer with a price/status). One item can have multiple listings over time. |
+| Purchase flow | Atomic transaction: debit buyer → hold funds in escrow (`pending_escrow`) → grant item. Platform fee computed server-side. |
+| Escrow | Configurable hold window (default 72h) before `pending_escrow` becomes available seller earnings. Refunds during the window reverse the sale. |
+| Fees | Single configurable `MARKETPLACE_FEE_RATE` (default `0.30`). `seller_net = floor(price * (1 - fee_rate))`. |
+| Creator balance | `creator_balances` table: `available` (earned, payable), `pending` (inside an open payout request), `lifetime_earned`. Updated in the same transaction as the sale completion. |
+| Payouts | Pluggable `PayoutProvider.pay()` with a no-op default (simulated external ref). Minimum payout threshold, admin review for large payouts. |
+| Idempotency | Every money-moving request carries a client-generated `Idempotency-Key`; duplicate keys return the original result. |
+| Rate limiting | Redis token-bucket dependency reused from the social feature for purchase/listing/payout endpoints. |
+| Moderation | Listings enforce content flags + age gate; moderators can `delist`/`remove`; fraud/chargeback reversal is an audited admin action. |
+
+## 5. User stories
+
+### US-1 Currency & wallet
+As a player, I can see my Credit balance and transaction history, and the system
+credits/debits my wallet only through server-authoritative events.
+
+**Acceptance criteria**
+- Exactly one wallet per user, created lazily on first use.
+- Balance is always a non-negative integer; no operation can make it negative.
+- Every mutation appends an immutable ledger row with amount, resulting balance,
+  reference, and idempotency key.
+- Retrying a request with the same idempotency key does not double-apply.
+- `GET` endpoints expose current balance and paged transaction history.
+
+### US-2 Premium purchase (buy Credits)
+As a player, I can purchase Credits with real money and have them credited only
+after the payment is confirmed.
+
+**Acceptance criteria**
+- A purchase session is created through the payment provider (or the no-op
+  default) and is idempotent.
+- Credits are granted exactly once, only after a verified provider confirmation
+  (webhook/confirm endpoint), never on client claim.
+- Purchase amounts are bounded and server-defined; clients cannot pick arbitrary
+  prices.
+- Confirmation is idempotent and audited (provider reference recorded).
+
+### US-3 Marketplace listing (sell)
+As a creator, I can list a catalog item for sale at a Credit price and
+manage/remove my listings.
+
+**Acceptance criteria**
+- A listing references a valid `catalog_item` owned by the seller (or an
+  authorized seller).
+- Price is bounded (min/max) and set server-side; status transitions are
+  explicit (`active`, `sold`, `delisted`, `removed_by_moderation`).
+- Only the seller (or a moderator) can update/remove a listing.
+- Listings are searchable/filterable (item type, price range, owner).
+
+### US-4 Marketplace purchase (buy)
+As a player, I can buy a listed item. The purchase is atomic, holds funds in
+escrow, grants the item, and splits the payment between platform and seller.
+
+**Acceptance criteria**
+- A single transaction debits the buyer, holds funds in escrow, and grants the
+  item — no partial states on failure.
+- Platform fee and seller net are computed server-side from the configured rate.
+- After the escrow hold window, funds move from escrow to the seller's
+  available balance.
+- Refunds during the hold window reverse the sale and return funds to the buyer.
+- Concurrent purchases of a one-of-a-kind listing cannot both succeed.
+
+### US-5 Creator payouts
+As a creator, I can view my earned balance, request a payout, and track its
+status; admins can review and approve/reject payouts.
+
+**Acceptance criteria**
+- Available balance is derived only from completed (escrow-released) sales and
+  completed payouts; it never goes negative.
+- Payout requests are bounded (min threshold, max per period) and rate-limited.
+- Large payouts require admin review; all payout requests carry an audit trail
+  (requested by, reviewed by, provider reference, status).
+- The payout provider is called exactly once; idempotent on retry.
+
+### US-6 Godot client
+As a player, I can manage Credits, browse/buy/sell marketplace items, and manage
+payouts from the game UI.
+
+**Acceptance criteria**
+- An API client handles JWT auth, HTTP, and idempotency keys for all economy
+  calls.
+- Dedicated screens: wallet + transaction history, marketplace browse/buy,
+  sell-listing, and creator payout.
+- The client never computes balances, fees, or seller nets — it only displays
+  server responses.
+
+## 6. Task breakdown
+
+Right-sized to 1–3 files / one coherent piece of functionality each. Task IDs
+are sequential for dependency chaining.
+
+| # | Task | Story | Depends on |
+|---|------|-------|-----------|
+| 1 | Wallet & ledger models + Alembic migration (`wallets`, `transactions`) | US-1 | — |
+| 2 | Wallet service (atomic credit/debit, idempotency, locking) + wallet/transactions API | US-1 | 1 |
+| 3 | Premium purchase: `PaymentProvider` interface + purchase/confirm endpoints | US-2 | 1 |
+| 4 | Catalog item & listing models + migration (`catalog_items`, `marketplace_listings`, `creator_balances`) | US-3 | 1 |
+| 5 | Marketplace listing API (create/list/search/update/remove) | US-3 | 4 |
+| 6 | Marketplace purchase service + API (atomic escrow, fee split, item grant) | US-4 | 2, 4, 5 |
+| 7 | Creator payout request models + API (`payout_requests`) | US-5 | 2, 6 |
+| 8 | Payout admin review + `PayoutProvider` + audit | US-5 | 7 |
+| 9 | Marketplace moderation + content-flag/age-gate enforcement | cross-cutting | 5, 6 |
+| 10 | Godot economy API client (auth + HTTP + idempotency) | US-6 | 2 |
+| 11 | Godot wallet & transaction history UI | US-6 | 10 |
+| 12 | Godot marketplace browse/buy UI | US-6 | 6, 10 |
+| 13 | Godot selling & payout UI | US-6 | 5, 7, 10 |
+
+## 7. Phasing
+
+- **Phase 1 (currency + payments):** tasks 1–3. The foundation — ledger and
+  money movement must be rock-solid before anything spends Credits.
+- **Phase 2 (marketplace):** tasks 4–6. Listing and atomic purchase with escrow.
+- **Phase 3 (payouts):** tasks 7–8. Turn released escrow into creator payouts.
+- **Phase 4 (moderation):** task 9. Lock down the marketplace against mature
+  content and abuse.
+- **Phase 5 (client):** tasks 10–13, each landing after its backend dependency.
+
+## 8. Data model sketch
+
+```text
+wallets
+  id                bigint PK
+  user_id           int UNIQUE FK -> users.id
+  balance           bigint NOT NULL DEFAULT 0  CHECK (balance >= 0)
+  created_at        timestamptz
+  updated_at        timestamptz
+
+transactions        (append-only ledger)
+  id                bigint PK
+  wallet_id         bigint FK -> wallets.id
+  type              enum(credit_purchase, marketplace_purchase,
+                        marketplace_sale, escrow_release, payout,
+                        refund, admin_adjustment)
+  amount            bigint NOT NULL            (signed)
+  balance_after     bigint NOT NULL
+  reference_type    text                        (e.g. "purchase", "sale", "payout_request")
+  reference_id      text
+  idempotency_key   text UNIQUE
+  metadata_json     jsonb
+  created_at        timestamptz
+
+catalog_items
+  id                bigint PK
+  owner_id          int FK -> users.id
+  asset_id          int FK -> assets.id (nullable; null for non-asset virtual items)
+  item_type         enum(asset, avatar_item, experience_pass)
+  name              text
+  description       text
+  metadata_json     jsonb
+  created_at        timestamptz
+
+marketplace_listings
+  id                bigint PK
+  catalog_item_id   bigint FK -> catalog_items.id
+  seller_id         int FK -> users.id
+  price             bigint NOT NULL CHECK (price > 0)
+  status            enum(active, sold, delisted, removed_by_moderation)
+  created_at        timestamptz
+  updated_at        timestamptz
+
+purchases
+  id                bigint PK
+  listing_id        bigint FK -> marketplace_listings.id
+  buyer_id          int FK -> users.id
+  seller_id         int FK -> users.id
+  price             bigint NOT NULL
+  platform_fee      bigint NOT NULL
+  seller_net        bigint NOT NULL
+  status            enum(pending_escrow, completed, refunded, reversed)
+  escrow_hold_until timestamptz
+  created_at        timestamptz
+
+creator_balances
+  id                bigint PK
+  user_id           int UNIQUE FK -> users.id
+  available         bigint NOT NULL DEFAULT 0
+  pending           bigint NOT NULL DEFAULT 0
+  lifetime_earned   bigint NOT NULL DEFAULT 0
+  updated_at        timestamptz
+
+payout_requests
+  id                bigint PK
+  creator_id        int FK -> users.id
+  amount            bigint NOT NULL CHECK (amount > 0)
+  status            enum(pending, approved, paid, rejected)
+  external_ref      text
+  provider_ref      text
+  requested_by      int FK -> users.id
+  reviewed_by       int FK -> users.id (nullable)
+  reviewed_at       timestamptz
+  created_at        timestamptz
+```
+
+## 9. Security, anti-fraud & audit
+
+- **Server-authoritative balances/fees:** clients never compute totals; amounts
+  are validated server-side against bounds and the current listing.
+- **Row locking:** wallet and creator-balance mutations use `SELECT ... FOR
+  UPDATE` within one transaction.
+- **Idempotency:** every money-moving endpoint requires an `Idempotency-Key`;
+  duplicate keys return the stored original outcome.
+- **Rate limiting:** purchase, listing, and payout endpoints are token-bucket
+  rate-limited per user.
+- **Escrow & reversibility:** funds are not payable until the hold window
+  elapses; chargebacks/refunds reverse before release.
+- **Moderation:** listings carry the item's effective content flags; mature
+  items require age verification (per `content_moderation.md`); moderators can
+  `delist`/`remove` and trigger audited reversals.
+- **Audit:** the ledger plus `payout_requests` review fields form an append-only
+  audit trail for every movement of value.
+
+## 10. Out of scope for this feature
+
+- Real Stripe/PayPal/KYC integrations (provider interfaces leave the hooks; the
+  defaults are deterministic no-ops).
+- Subscriptions, recurring billing, or premium memberships.
+- Gift cards, promotional codes, or user-to-user Credit transfers.
+- Partial refunds, chargeback disputes, and seller tax/VAT handling.
+- In-world vending machines / scripted economy triggers (future, built on this
+  ledger via the scripting sandbox).