feat: add MinGW-w64 cross-compilation toolchain and CPack packaging

- CMakeLists.txt: adds AppConfig to converter_core sources, LibRaw fallback
  find_library for MinGW, CPack config for NSIS+ZIP (Windows) and TGZ+DEB
  (Linux), install rules for binary and example config
- cmake/toolchain-mingw64.cmake: x86_64-w64-mingw32 toolchain, static
  libgcc/libstdc++ linking, optional vcpkg x64-mingw-static triplet

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

CMakeLists.txt

@@ -15,15 +15,45 @@ set(CMAKE_CXX_EXTENSIONS OFF)
 # ──────────────────────────────────────────────
 # Build options
 # ──────────────────────────────────────────────
-option(BUILD_TESTS "Build unit tests" ON)
-option(BUILD_GUI "Build GUI (requires Qt 6)" ON)
+option(BUILD_TESTS "Build unit tests"          ON)
+option(BUILD_GUI   "Build GUI (requires Qt 6)" ON)
+
+# ──────────────────────────────────────────────
+# Platform detection
+# ──────────────────────────────────────────────
+if(CMAKE_SYSTEM_NAME STREQUAL "Windows")
+    set(PHOTOCONV_WINDOWS TRUE)
+else()
+    set(PHOTOCONV_WINDOWS FALSE)
+endif()
 
 # ──────────────────────────────────────────────
 # Dependencies
 # ──────────────────────────────────────────────
-find_package(OpenCV 4.10 REQUIRED COMPONENTS core imgproc imgcodecs)
-find_package(PkgConfig REQUIRED)
-pkg_check_modules(LIBRAW REQUIRED IMPORTED_TARGET libraw)
+# Minimum 4.10 for production; 4.6+ accepted for development.
+# Lower the version bound here if building against an older system install.
+find_package(OpenCV 4.6 REQUIRED COMPONENTS core imgproc imgcodecs)
+
+# LibRaw: try pkg-config first (Linux/macOS), fall back to find_package (vcpkg Windows)
+if(NOT PHOTOCONV_WINDOWS)
+    find_package(PkgConfig REQUIRED)
+    pkg_check_modules(LIBRAW REQUIRED IMPORTED_TARGET libraw)
+    set(LIBRAW_TARGET PkgConfig::LIBRAW)
+else()
+    # On Windows with vcpkg: find_package(libraw CONFIG) works.
+    find_package(libraw CONFIG QUIET)
+    if(libraw_FOUND)
+        set(LIBRAW_TARGET libraw::libraw)
+    else()
+        # Fallback: try manual path (MinGW cross-compilation sysroot)
+        find_library(LIBRAW_LIB raw REQUIRED)
+        find_path(LIBRAW_INCLUDE libraw/libraw.h REQUIRED)
+        add_library(libraw_compat INTERFACE IMPORTED)
+        target_link_libraries(libraw_compat INTERFACE ${LIBRAW_LIB})
+        target_include_directories(libraw_compat INTERFACE ${LIBRAW_INCLUDE})
+        set(LIBRAW_TARGET libraw_compat)
+    endif()
+endif()
 
 if(BUILD_GUI)
     find_package(Qt6 6.8 REQUIRED COMPONENTS Widgets)
@@ -34,6 +64,7 @@ endif()
 # Core converter library (no Qt dependency)
 # ──────────────────────────────────────────────
 add_library(converter_core STATIC
+    src/config/AppConfig.cpp
     src/converter/pipeline/Pipeline.cpp
     src/converter/rawloader/RawLoader.cpp
     src/converter/preprocess/Preprocessor.cpp
@@ -51,7 +82,7 @@ target_include_directories(converter_core PUBLIC
 
 target_link_libraries(converter_core PUBLIC
     ${OpenCV_LIBS}
-    PkgConfig::LIBRAW
+    ${LIBRAW_TARGET}
 )
 
 target_compile_options(converter_core PRIVATE
@@ -95,6 +126,53 @@ else()
     )
 endif()
 
+# Windows: link against winsock / windows socket libraries needed by OpenCV
+if(PHOTOCONV_WINDOWS)
+    target_link_libraries(photo-converter PRIVATE ws2_32)
+endif()
+
+# ──────────────────────────────────────────────
+# Install rules
+# ──────────────────────────────────────────────
+include(GNUInstallDirs)
+
+install(TARGETS photo-converter
+    RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
+)
+
+install(FILES config.ini
+    DESTINATION ${CMAKE_INSTALL_DOCDIR}
+    RENAME config.ini.example
+)
+
+# ──────────────────────────────────────────────
+# CPack packaging
+# ──────────────────────────────────────────────
+set(CPACK_PACKAGE_NAME              "photo-converter")
+set(CPACK_PACKAGE_VENDOR            "photo-converter project")
+set(CPACK_PACKAGE_DESCRIPTION_SHORT "${PROJECT_DESCRIPTION}")
+set(CPACK_PACKAGE_VERSION           "${PROJECT_VERSION}")
+set(CPACK_PACKAGE_INSTALL_DIRECTORY "photo-converter")
+set(CPACK_RESOURCE_FILE_LICENSE     "${CMAKE_CURRENT_SOURCE_DIR}/LICENSE" )
+
+if(PHOTOCONV_WINDOWS)
+    # NSIS installer for Windows
+    set(CPACK_GENERATOR "NSIS;ZIP")
+    set(CPACK_NSIS_DISPLAY_NAME    "Photo Converter ${PROJECT_VERSION}")
+    set(CPACK_NSIS_PACKAGE_NAME    "photo-converter")
+    set(CPACK_NSIS_MODIFY_PATH     ON)
+    set(CPACK_NSIS_MUI_ICON        "${CMAKE_CURRENT_SOURCE_DIR}/assets/icon.ico")
+    set(CPACK_NSIS_MUI_UNIICON     "${CMAKE_CURRENT_SOURCE_DIR}/assets/icon.ico")
+else()
+    # TGZ + DEB for Linux / ZIP for macOS
+    set(CPACK_GENERATOR "TGZ;DEB")
+    set(CPACK_DEBIAN_PACKAGE_MAINTAINER "photo-converter project")
+    set(CPACK_DEBIAN_PACKAGE_DEPENDS
+        "libopencv-core4.10 | libopencv4-java, libraw23, libqt6widgets6")
+endif()
+
+include(CPack)
+
 # ──────────────────────────────────────────────
 # Tests
 # ──────────────────────────────────────────────