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/title_scene.cpp

@@ -4,7 +4,6 @@
 
 #include <algorithm>
 #include <cstdint>
-#include <iostream>
 #include <string>
 #include <utility>
 
@@ -26,6 +25,7 @@
 #include "utils/defaults.hpp"
 #include "utils/defines.hpp"
 #include "utils/easing.hpp"
+#include "utils/log.hpp"
 
 namespace {
 
@@ -72,7 +72,7 @@ TitleScene::TitleScene(std::shared_ptr<Text> condensed_font, std::shared_ptr<Tex
       game_logo_(std::move(game_logo)),
       mini_logo_(std::move(mini_logo)),
       timer_ms_(UiConfig::get().titleDurationMs()) {
-    std::cout << "[scene] " << SCENE_NAME << " start\n";
+    Log::info("scene", "{} start", SCENE_NAME);
     const auto& hh = UiConfig::get().titleHeatHaze();
     if (hh.enabled) {
         heat_haze_.emplace(Effects::HeatHaze::Params{
@@ -190,7 +190,7 @@ void TitleScene::enterStarting(DebugConfig::StartingPlayers players) {
     if (auto* audio = Audio::get(); audio != nullptr) {
         audio->fadeOutMusic(UiConfig::get().titleMusicFadeOutMs());
     }
-    std::cout << "[scene] " << SCENE_NAME << " STARTING (players=" << DebugConfig::toString(players) << ")\n";
+    Log::info("scene", "{} STARTING (players={})", SCENE_NAME, DebugConfig::toString(players));
 }
 
 void TitleScene::tickIdle(int delta_ms, bool p1_start, bool p2_start) {
@@ -255,7 +255,7 @@ void TitleScene::enterAttract() {
     if (attract_fade_) {
         attract_fade_->begin(UiConfig::get().titleAttractFadeToBlackMs());
     }
-    std::cout << "[scene] " << SCENE_NAME << " ATTRACT_OUT\n";
+    Log::info("scene", "{} ATTRACT_OUT", SCENE_NAME);
 }
 
 void TitleScene::advanceToIntro(DebugConfig::StartingPlayers players) {