refactor(log): migra els subsistemes restants i elimina iostream

Acaba la migració dels std::cout/cerr a Log::*:

- core/locale, core/ui/ui_config, core/rendering/{screen,text,gif,
  surface, sprite/animated_sprite, sdl3gpu/*}.
- game/{options, debug_config, editor/editor_config, levels/level_manager,
  map/{map,tilemap,paint_layer}, entities/entity_manager_loadlevel}.

Severitats coherents: warns per a configs absents amb fallback,
errors per a YAML malformat o E/S fallida, infos per a estats.

Resultat:
- 0 occurrences de std::cout/std::cerr a source/.
- Cap #include <iostream> orfà (eliminat de surface.cpp).
- Output funcional idèntic al històric; AEE_LOG filtra (ex.
  `AEE_LOG=warn` només mostra warnings, `AEE_LOG=*:warn,Tag:info`
  combina globals i overrides).

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

source/core/rendering/surface.cpp

@@ -2,7 +2,6 @@
 
 #include <algorithm>
 #include <cstring>
-#include <iostream>
 #include <stdexcept>
 #include <vector>