fix(client): address PR #67 round 2 — broken tests, BBCode escape, expiry loop

- Add missing _test_input_queue proxy to SimBridge (26 call sites across
  6 test files broken by TestHarness extraction)
- Parent quit dialog to SceneTree root instead of caller node to prevent
  orphaned reference if caller freed before user responds
- Remove deprecated rng.randomize() call (Godot 4 auto-seeds)
- Clear debug overlay state (_npc_paths, tick timing) on session change
  via new GameState.game_id_changed signal to prevent entity ID collisions
- Update settings_dialog quit_to_menu() call site (no-arg signature)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

client/scripts/autoloads/game_state.gd

@@ -1,5 +1,7 @@
 extends Node
 
+signal game_id_changed(new_id: String)
+
 # Updated each frame from ObserverSnapshot data (Protocol format: {tick, entities, tiles}).
 # Entities use Protocol decoded format: {entity_id, x, y, z, kind: {variant, data}}.
 # Tiles use format: [{x, y, z, type}].
@@ -8,7 +10,10 @@ var current_snapshot: Dictionary = {}
 # D-085 (#258): Active game session identifier. Format: <YYYYMMDD>-<HHMMSS>-<hex6>
 # Set by SessionManager.new_game() or SessionManager.resume_game().
 # Empty string when no session is active (main menu state).
-var current_game_id: String = ""
+var current_game_id: String = "":
+	set(v):
+		current_game_id = v
+		game_id_changed.emit(v)
 var current_tick: int = 0
 var player_position: Vector2 = Vector2.ZERO
 var visible_entities: Array = []