WIP checkpoint: Address review feedback: Fix: navigating Play -> Back logs the user out (should stay logged in)

The actual fix (main_menu.gd's _ready() checking ApiClient.has_token()
and restoring authenticated state via get_me()) was already correct --
verified this directly by instrumenting frame-by-frame state and seeing
it resolve properly in ~5 frames. The test wrapping it was the real
problem: _wait_for_menu_ready() only waited 2 frames total before
checking assertions, nowhere near enough for a real HTTP round-trip, so
every run failed on a fix that actually worked.

Root fix: added a real auth_state_ready signal to main_menu.gd, emitted
once _ready()'s session check has actually resolved (either branch --
authenticated or logged-out). The test now awaits that signal directly
instead of guessing from a frame count or from UI properties that are
ambiguous mid-await (AuthButtonsRow.visible is true both before the
check resolves AND in a genuine logged-out end state, which is exactly
what made an earlier polling-based fix attempt here also flaky).

Also fixed a second real bug in the test itself: unique_id used
Time.get_ticks_msec() (process-relative, not wall-clock), colliding
with a previous run's still-present data -- same flakiness class fixed
elsewhere this session, same fix (wall-clock ms + random suffix).

Verified: 12/12 passing across 3 consecutive runs against a real
backend.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

scripts/main_menu.gd

@@ -8,9 +8,22 @@ extends Control
 ##
 ## On successful auth the token is stored via ApiClient, AuthButtonsRow hides,
 ## the welcome label shows the username, and the Play button becomes enabled.
+##
+## When returning from another scene (e.g. world_list), _ready() checks whether
+## ApiClient already holds a valid token. If so, it restores the authenticated
+## UI state (Play enabled, welcome label visible) instead of forcing the user
+## back to the login form.
 
 
-# ── UI references ────────────────────────────────────────────────────────────
+## Emitted once _ready()'s session check (has_token() + the awaited
+## get_me() call) has actually resolved, whichever way -- lets a test (or
+## anything else) know the UI state is trustworthy now, rather than
+## guessing from a frame count or from UI properties that are ambiguous
+## mid-await (e.g. AuthButtonsRow.visible is true both before the check
+## resolves AND in a genuine logged-out end state).
+signal auth_state_ready
+
+# ─── UI references ────────────────────────────────────────────────────────────
 
 var _auth_buttons_row: HBoxContainer
 var _login_button: Button
@@ -32,7 +45,7 @@ var _is_register_mode: bool = false
 var _is_authenticating: bool = false
 
 
-# ── Lifecycle ────────────────────────────────────────────────────────────────
+# ─── Lifecycle ────────────────────────────────────────────────────────────────
 
 func _ready() -> void:
 	# Cache node references.
@@ -52,7 +65,46 @@ func _ready() -> void:
 	_play_button = $CenterContainer/VBoxContainer/PlayButton
 	_quit_button = $CenterContainer/VBoxContainer/QuitButton
 
-	# Initial state.
+	# Default to Play being gated. When a token exists, the async session
+	# check below may take several frames (a real get_me() round-trip);
+	# keeping the button disabled until validation succeeds prevents a fast
+	# click from navigating to world_list with an expired/invalid token.
+	_play_button.disabled = true
+
+	# Check whether a valid session already exists (e.g. user logged in,
+	# navigated to world_list, then clicked Back). If so, restore the
+	# authenticated UI state instead of forcing the login form again.
+	if ApiClient.has_token():
+		var me_result: Dictionary = await ApiClient.get_me()
+		if me_result.ok and me_result.data is Dictionary:
+			var username: String = str((me_result.data as Dictionary).get("username", ""))
+			if username != "":
+				_show_authenticated(username)
+				auth_state_ready.emit()
+				return
+
+	# Token missing or invalid — fall through to logged-out state.
+	_reset_to_logged_out()
+	auth_state_ready.emit()
+
+
+## Restore the UI to the authenticated state (Play enabled, welcome label,
+## auth buttons hidden).
+func _show_authenticated(username: String) -> void:
+	_auth_panel.visible = true
+	_status_label.visible = false
+	_welcome_label.text = "Welcome, %s!" % username
+	_welcome_label.visible = true
+	_email_edit.visible = false
+	_dob_edit.visible = false
+	_play_button.disabled = false
+	_auth_buttons_row.visible = false
+	print("Restored authenticated session for: ", username)
+
+
+## Reset the UI to the logged-out state (Play disabled, auth panel hidden,
+## login/register buttons visible).
+func _reset_to_logged_out() -> void:
 	_auth_panel.visible = false
 	_status_label.visible = false
 	_welcome_label.visible = false
@@ -62,7 +114,7 @@ func _ready() -> void:
 	_update_auth_mode_ui()
 
 
-# ── Play / Quit ──────────────────────────────────────────────────────────────
+# ─── Play / Quit ─────────────────────────────────────────────────────────────
 
 func _on_play_button_pressed() -> void:
 	if _play_button.disabled:
@@ -76,7 +128,7 @@ func _on_quit_button_pressed() -> void:
 	get_tree().quit()
 
 
-# ── Auth panel toggle ────────────────────────────────────────────────────────
+# ─── Auth panel toggle ───────────────────────────────────────────────────────
 
 func _on_login_button_pressed() -> void:
 	"""Show the auth panel, called from AuthButtonsRow/LoginButton."""
@@ -94,7 +146,7 @@ func _on_register_button_pressed() -> void:
 	_username_edit.grab_focus()
 
 
-# ── Mode toggle (Login / Register) ───────────────────────────────────────────
+# ─── Mode toggle (Login / Register) ──────────────────────────────────────────
 
 func _on_mode_toggle_toggled(button_pressed: bool) -> void:
 	_is_register_mode = button_pressed
@@ -116,7 +168,7 @@ func _update_auth_mode_ui() -> void:
 		_dob_edit.visible = false
 
 
-# ── Auth submission ──────────────────────────────────────────────────────────
+# ─── Auth submission ─────────────────────────────────────────────────────────
 
 func _on_auth_button_pressed() -> void:
 	"""Handle login or register button press."""
@@ -187,7 +239,7 @@ func _on_auth_complete(result: Dictionary) -> void:
 		_show_status(result.detail)
 
 
-# ── Status helpers ───────────────────────────────────────────────────────────
+# ─── Status helpers ──────────────────────────────────────────────────────────
 
 func _show_status(message: String) -> void:
 	_status_label.text = message
@@ -199,7 +251,7 @@ func _clear_status() -> void:
 	_status_label.visible = false
 
 
-# ── Validation ───────────────────────────────────────────────────────────────
+# ─── Validation ──────────────────────────────────────────────────────────────
 
 func _is_valid_date(date_str: String) -> bool:
 	"""Check if a string looks like a valid YYYY-MM-DD date."""

scripts/smoke_test_main_menu_back.gd

@@ -0,0 +1,154 @@
+extends SceneTree
+## Regression test for the Play -> Back navigation bug.
+##
+## The reported bug: after logging in and clicking Play, the user lands on
+## world_list.tscn; clicking Back returns to main_menu.tscn, but the menu
+## reset to a fully logged-out state (Play disabled, login form showing)
+## even though ApiClient still held a valid token. main_menu.gd's _ready()
+## used to unconditionally reset the UI on every scene load.
+##
+## This test drives the real navigation flow (change_scene_to_file) against
+## a live backend:
+##   1. Register a unique user so ApiClient holds a valid token.
+##   2. Load main_menu.tscn and assert it restores the authenticated state.
+##   3. Click Play -> world_list.tscn.
+##   4. Click Back -> main_menu.tscn.
+##   5. Assert the menu is STILL authenticated (Play enabled, welcome label
+##      actually visible in the tree, login/register buttons hidden).
+##
+## Run with:
+##     godot --headless --path . --script res://scripts/smoke_test_main_menu_back.gd
+##
+## Requires the backend to be running (default base URL
+## `application/agp/api_base_url` -> http://127.0.0.1:8000).
+
+const USERNAME := "backnav_%d"
+const EMAIL := "backnav_%d@test.example.com"
+const PASSWORD := "BackNav123!"
+const DOB := "2000-01-01"
+
+var passed := 0
+var failed := 0
+
+
+func _initialize() -> void:
+	_run()
+
+
+func _run() -> void:
+	await process_frame
+
+	var api := root.get_node("ApiClient")
+	if api == null:
+		printerr("FAIL: ApiClient autoload not found")
+		quit(1)
+		return
+
+	# 1. Establish a real, valid session exactly the way a user would.
+	randomize()
+	var unique_id: int = int(Time.get_unix_time_from_system() * 1000) + randi() % 100000
+	var username := USERNAME % unique_id
+	var email := EMAIL % unique_id
+	print("\n=== Setup: register ", username, " ===")
+	var register_result: Dictionary = await api.register(username, email, PASSWORD, DOB)
+	if not _check("register succeeds", register_result.ok):
+		print("  detail: ", register_result.detail)
+		_finish()
+		return
+	_check("ApiClient stores token after register", api.has_token())
+
+	# 2. First visit to the main menu: should already show the authenticated
+	#    state (no login form, Play enabled).
+	change_scene_to_file("res://scenes/main_menu.tscn")
+	# change_scene_to_file defers the actual swap -- a couple frames is
+	# plenty for the scene object itself to exist (unlike the real
+	# get_me() network round-trip afterward, which is what auth_state_ready
+	# actually waits for below).
+	for i in 5:
+		await process_frame
+		if current_scene is Control:
+			break
+
+	var menu: Control = current_scene
+	if menu == null or not menu is Control:
+		printerr("FAIL: main_menu.tscn did not become current_scene")
+		_finish()
+		return
+	await menu.auth_state_ready
+	_check("first main menu visit restores authenticated state", _is_authenticated(menu))
+
+	# 3. Play -> world_list.tscn (real button press).
+	var play_button: Button = menu.get_node("CenterContainer/VBoxContainer/PlayButton")
+	play_button.pressed.emit()
+	await _wait_for_scene_change(menu)
+
+	var world_list_scene := current_scene
+	if world_list_scene == null or world_list_scene == menu:
+		printerr("FAIL: world_list.tscn did not become current_scene after Play")
+		_finish()
+		return
+
+	# 4. Back -> main_menu.tscn (real button press).
+	var back_button: Button = world_list_scene.get_node("VBoxContainer/HeaderHBox/BackButton")
+	back_button.pressed.emit()
+	await _wait_for_scene_change(world_list_scene)
+
+	menu = current_scene
+	if menu == null or not menu is Control:
+		printerr("FAIL: main_menu.tscn did not become current_scene after Back")
+		_finish()
+		return
+
+	# The new main_menu instance's own _ready() is *also* awaiting a real
+	# get_me() call -- _wait_for_scene_change only confirms the scene
+	# object exists, not that its authenticated-state fields have been
+	# set yet. Wait for the real signal, not a guess.
+	await menu.auth_state_ready
+
+	# 5. THE regression assertion: still logged in after returning.
+	_check("main menu stays authenticated after Play -> Back", _is_authenticated(menu))
+
+	_finish()
+
+
+func _is_authenticated(menu: Control) -> bool:
+	var play_button: Button = menu.get_node("CenterContainer/VBoxContainer/PlayButton")
+	var welcome_label: Label = menu.get_node("CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/WelcomeLabel")
+	var auth_buttons_row: HBoxContainer = menu.get_node("CenterContainer/VBoxContainer/AuthButtonsRow")
+	var auth_panel: PanelContainer = menu.get_node("CenterContainer/VBoxContainer/AuthPanel")
+
+	_check("Play enabled", not play_button.disabled)
+	# WelcomeLabel lives inside AuthPanel, so `.visible` alone is a
+	# false-positive: the label can have visible=true while its parent is
+	# hidden and it renders as nothing. `is_visible_in_tree()` is the
+	# check that proves the user can actually see the welcome message.
+	_check("Welcome label visible in tree", welcome_label.is_visible_in_tree())
+	_check("Auth buttons row hidden", not auth_buttons_row.visible)
+	_check("Auth panel visible (it contains the welcome label)", auth_panel.visible)
+
+	return (not play_button.disabled) \
+		and welcome_label.is_visible_in_tree() \
+		and not auth_buttons_row.visible \
+		and auth_panel.visible
+
+
+func _wait_for_scene_change(previous_scene: Node) -> void:
+	for i in 20:
+		await process_frame
+		if current_scene != previous_scene and current_scene != null:
+			return
+
+
+func _check(description: String, condition: bool) -> bool:
+	if condition:
+		print("  PASS: ", description)
+		passed += 1
+	else:
+		printerr("  FAIL: ", description)
+		failed += 1
+	return condition
+
+
+func _finish() -> void:
+	print("\n=== SMOKE RESULT: %d/%d passed ===" % [passed, passed + failed])
+	quit(0 if failed == 0 else 1)

scripts/smoke_test_main_menu_full_flow.gd

@@ -60,7 +60,7 @@ func _run() -> void:
 	await instance._on_auth_button_pressed()
 
 	_check("Play became enabled after real register submission", not play_button.disabled)
-	_check("Welcome label visible", welcome_label.visible)
+	_check("Welcome label visible in tree", welcome_label.is_visible_in_tree())
 	_check("Auth buttons row hid itself after success", not auth_buttons_row.visible)
 
 	print("\n=== SMOKE RESULT: %d/%d passed ===" % [passed, passed + failed])