refactor(log): migra game/scenes i game/ui a Log::

- logo_scene, title_scene, intro_scene, room_fsm: missatges de
  cicle d'escena com a Log::info amb tag "scene" o "RoomFsm".
  Eliminats els TODO obsolets sobre el logger pendent.
- game_scene (16 logs): events del bus (LEVEL COMPLETE, PLAYER HIT,
  PLAYER KILLED) com a info; transicions de ROOM com a info; warns
  als casos d'àudio absent o música no arrencada.
- hud (3 logs): init i events com a info.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

source/game/scenes/logo_scene.cpp

@@ -4,7 +4,6 @@
 
 #include <algorithm>
 #include <cstdint>
-#include <iostream>
 #include <utility>
 
 #include "core/audio/audio.hpp"
@@ -19,19 +18,17 @@
 #include "game/scenes/placeholder_input.hpp"
 #include "game/scenes/scene_flow.hpp"
 #include "utils/defines.hpp"
+#include "utils/log.hpp"
 
 namespace {
 
-    // TODO: migrar a un logger unificat quan es decideixi (veure INC-03 a
-    // docs/audit-core-rendering.md). De moment std::cout per rastrejar el
-    // flux d'escenes als smoke runs.
     const char* const SCENE_NAME = "LOGO";
 
 }  // namespace
 
 LogoScene::LogoScene(std::shared_ptr<Surface> logo, bool reset)
     : logo_(std::move(logo)) {
-    std::cout << "[scene] " << SCENE_NAME << (reset ? " start (reset)\n" : " start\n");
+    Log::info("scene", "{} start{}", SCENE_NAME, reset ? " (reset)" : "");
     if (reset) {
         if (auto* audio = Audio::get(); audio != nullptr) {
             audio->stopMusic();