Migrate to CMake-based build with packaging

Major build system refactoring:

**CMake (build authority)**:
- Auto-discovers .cpp files (GLOB_RECURSE in source/core/ and source/game/)
- No manual file list maintenance needed
- Excludes source/legacy/ automatically
- Generates build/project.h from template

**Makefile (simplified wrapper)**:
- Delegates compilation to CMake (make → cmake --build build)
- Contains 5 release packaging targets:
  * macos_release: .app bundle + .dmg (Apple Silicon)
  * linux_release: .tar.gz
  * windows_release: .zip with .exe + DLLs
  * windows_cross: cross-compile from Linux/macOS
  * rpi_release: ARM64 cross-compile
- Complex packaging logic preserved (code signing, symlinks, DMG creation)

**Benefits**:
- Add new .cpp file → automatically compiled (no manual updates)
- Single source of truth in CMakeLists.txt (no duplication)
- IDE-friendly (VSCode, CLion, etc.)
- Complete packaging support (5 platforms)

**Files changed**:
- CMakeLists.txt: GLOB_RECURSE replaces 23-file hardcoded list
- Makefile: Simplified compilation + added 5 release targets (~220 lines)
- CLAUDE.md: Updated build system documentation
- escena_titol.cpp: Fixed include path (build/project.h → project.h)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

CMakeLists.txt

@@ -31,33 +31,23 @@ endif()
 # Configurar archivo de versión
 configure_file(${CMAKE_SOURCE_DIR}/source/project.h.in ${CMAKE_BINARY_DIR}/project.h @ONLY)
 
-# --- LISTA DE FUENTES ---
+# --- LISTA DE FUENTES (AUTO-DESCUBRIMIENTO) ---
+# Buscar automáticamente todos los archivos .cpp en core/, game/ y main.cpp
+file(GLOB_RECURSE CORE_SOURCES "${CMAKE_SOURCE_DIR}/source/core/*.cpp")
+file(GLOB_RECURSE GAME_SOURCES "${CMAKE_SOURCE_DIR}/source/game/*.cpp")
 set(APP_SOURCES
+    ${CORE_SOURCES}
+    ${GAME_SOURCES}
     source/main.cpp
-    source/core/system/director.cpp
-    source/core/system/global_events.cpp
-    source/core/rendering/sdl_manager.cpp
-    source/core/rendering/line_renderer.cpp
-    source/core/rendering/color_oscillator.cpp
-    source/core/rendering/polygon_renderer.cpp
-    source/core/rendering/primitives.cpp
-    source/core/rendering/shape_renderer.cpp
-    source/core/graphics/shape.cpp
-    source/core/graphics/shape_loader.cpp
-    source/core/graphics/vector_text.cpp
-    source/core/graphics/starfield.cpp
-    source/core/audio/audio.cpp
-    source/core/audio/audio_cache.cpp
-    source/game/options.cpp
-    source/game/escenes/escena_logo.cpp
-    source/game/escenes/escena_titol.cpp
-    source/game/escenes/escena_joc.cpp
-    source/game/entities/nau.cpp
-    source/game/entities/bala.cpp
-    source/game/entities/enemic.cpp
-    source/game/effects/debris_manager.cpp
 )
 
+# Excluir archivos legacy (código Pascal de referencia)
+list(FILTER APP_SOURCES EXCLUDE REGEX ".*/legacy/.*")
+
+# Log de archivos encontrados (útil para debug)
+list(LENGTH APP_SOURCES APP_SOURCES_COUNT)
+message(STATUS "Archivos .cpp encontrados: ${APP_SOURCES_COUNT}")
+
 # Configuración de SDL3
 find_package(SDL3 REQUIRED CONFIG REQUIRED COMPONENTS SDL3)
 message(STATUS "SDL3 encontrado: ${SDL3_INCLUDE_DIRS}")