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/ui/debug_overlay.gd

@@ -77,6 +77,15 @@ func _ready() -> void:
 	_dev_mode = OS.is_debug_build()
 	visible = false
 	_cached_font = ThemeDB.fallback_font
+	# Clear NPC path history on session change to prevent entity ID collisions
+	GameState.connect("game_id_changed", _on_game_id_changed)
+
+
+func _on_game_id_changed(_new_id: String) -> void:
+	_npc_paths.clear()
+	_tick_deltas.clear()
+	_tick_times.clear()
+	_last_tick_processed = -1
 
 
 func _unhandled_input(event: InputEvent) -> void: