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/ui/settings_dialog.gd

@@ -163,7 +163,7 @@ func _draw() -> void:
 
 func _on_quit_to_menu() -> void:
 	close()
-	SessionManager.quit_to_menu(get_tree().root)
+	SessionManager.quit_to_menu()
 
 
 static func _format_db(db: float) -> String: