Fix real scene collision + a real regression from removing the Server autoload

Two genuine bugs, found by reproducing rather than trusting the branch's
own state:

1. scenes/player.tscn collided with PC2's client-side player scene at the
   exact same path (server-authoritative PlayerNode vs. the local
   single-player character) -- whichever merged last would silently
   overwrite the other. The branch's own last commit had literally
   committed unresolved <<<<<<< conflict markers into the file instead of
   resolving them. Renamed the server's version to
   scenes/server_player.tscn, restored scenes/player.tscn to match main's
   real client scene exactly, repointed scripts/server.gd's preload.

2. scenes/server.tscn's root Node had no script attached at all -- it only
   ever worked before because project.godot had `Server` registered as a
   project-wide autoload (the exact wholesale-overwrite this task was
   already asked to fix). Once that autoload was correctly removed,
   nothing attached server.gd to the scene tree anymore and the dedicated
   server silently did nothing. Attached scripts/server.gd directly to
   scenes/server.tscn's root node instead.

Verified: godot --headless --import/--quit both clean, full 10-suite
client smoke test all passing, and the dedicated server actually listens
on UDP port 7777 when launched explicitly (`godot --path . scenes/server.tscn`)
-- confirmed with `ss -ulnp`, not just trusting the startup print (first
checked with `ss -tlnp`, which only shows TCP and falsely suggested it
wasn't listening at all; ENet is UDP).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01M6rUEynmv2QmweocAQYARN

scenes/player.tscn

@@ -1,11 +1,3 @@
-<<<<<<< HEAD
-[gd_scene load_steps=2 format=3]
-
-[ext_resource type="Script" path="res://scripts/player_spawner.gd" id="1"]
-
-[node name="Player" type="CharacterBody3D"]
-script = ExtResource("1")
-=======
 [gd_scene load_steps=3 format=3 uid="uid://player_scene_001"]
 
 [ext_resource type="Script" path="res://scripts/player.gd" id="1_player"]
@@ -30,4 +22,3 @@ mesh = SubResource("CapsuleMesh1")
 [node name="Camera3D" type="Camera3D" parent="."]
 transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0.6, 0)
 current = true
->>>>>>> origin/main

scenes/server.tscn

@@ -1,3 +1,6 @@
-[gd_scene load_steps=1 format=3]
+[gd_scene load_steps=2 format=3]
+
+[ext_resource type="Script" path="res://scripts/server.gd" id="1_server"]
 
 [node name="Server" type="Node"]
+script = ExtResource("1_server")

scenes/server_player.tscn

@@ -0,0 +1,6 @@
+[gd_scene load_steps=2 format=3]
+
+[ext_resource type="Script" path="res://scripts/player_spawner.gd" id="1"]
+
+[node name="Player" type="CharacterBody3D"]
+script = ExtResource("1")

scripts/server.gd

@@ -37,7 +37,7 @@ var _player_scene: PackedScene
 
 func _ready() -> void:
 	# Preload the player scene once.
-	_player_scene = preload("res://scenes/player.tscn")
+	_player_scene = preload("res://scenes/server_player.tscn")
 
 	# Create and assign the ENet server peer.
 	network_peer = _create_server_peer()