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/session_manager.gd

@@ -22,7 +22,6 @@ func new_game() -> String:
 		now.hour, now.minute, now.second,
 	]
 	var rng := RandomNumberGenerator.new()
-	rng.randomize()
 	var hex_seed := "%06x" % (rng.randi() & 0xFFFFFF)
 	var game_id := "%s-%s" % [timestamp, hex_seed]
 	var save_path := SAVES_DIR + game_id + "/"
@@ -69,16 +68,15 @@ func list_game_dirs() -> Array:
 
 
 ## Show "Save before quitting?" confirmation dialog, then return to main menu.
-## node: the calling scene node (used as dialog parent).
 ## #554: The actual F5 save will be wired here once server supports SaveCommand.
-func quit_to_menu(node: Node) -> void:
+func quit_to_menu() -> void:
 	if _quit_dialog != null and is_instance_valid(_quit_dialog):
 		return  # Dialog already open
 	_quit_dialog = ConfirmationDialog.new()
 	_quit_dialog.dialog_text = UIStrings.get_text("menu.confirm_quit")
 	_quit_dialog.ok_button_text = UIStrings.get_text("menu.confirm_yes")
 	_quit_dialog.cancel_button_text = UIStrings.get_text("menu.confirm_no")
-	node.add_child(_quit_dialog)
+	get_tree().root.add_child(_quit_dialog)
 	_quit_dialog.confirmed.connect(_do_quit_to_menu)
 	_quit_dialog.canceled.connect(_cleanup_quit_dialog)
 	_quit_dialog.popup_centered()