feat: dual time zones, autostart, tray icon, config relocation, tests

- Dual clock (primary/secondary time zone) with IANA picker, persisted in XML
- AutoStartManager: macOS LaunchAgent (com.clouck.clock, RunAtLoad)
- Tray icon: template image, light/dark adaptation, toggle + quit menu
- ConfigManager: default path moved to QStandardPaths::AppConfigLocation
- Qt Test suite (ConfigManager, AutoStartManager) wired into CTest
- GitHub origin renamed to upstream; private Gitea repo as origin

CMakeLists.txt

@@ -4,6 +4,8 @@ project(Clouck)
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
+include(CTest)
+
 # Find Qt6
 find_package(Qt6 REQUIRED COMPONENTS Core Widgets)
 
@@ -23,12 +25,14 @@ qt6_standard_project_setup()
 # Sources
 set(SOURCES
     main.cpp
+    autostart_manager.cpp
     clock_widget.cpp
     config_manager.cpp
     window_helper.cpp
 )
 
 set(HEADERS
+    autostart_manager.h
     clock_widget.h
     config_manager.h
     window_helper.h
@@ -73,3 +77,27 @@ install(TARGETS Clouck
     RUNTIME DESTINATION bin
     BUNDLE DESTINATION bin
 )
+
+if(BUILD_TESTING)
+    find_package(Qt6 REQUIRED COMPONENTS Test)
+
+    qt6_add_executable(ConfigManagerTest
+        tests/config_manager_test.cpp
+        config_manager.cpp
+        config_manager.h
+    )
+    target_include_directories(ConfigManagerTest PRIVATE ${CMAKE_CURRENT_SOURCE_DIR})
+    target_link_libraries(ConfigManagerTest PRIVATE Qt6::Core Qt6::Gui Qt6::Test)
+
+    add_test(NAME ConfigManagerTest COMMAND ConfigManagerTest)
+
+    qt6_add_executable(AutoStartManagerTest
+        tests/autostart_manager_test.cpp
+        autostart_manager.cpp
+        autostart_manager.h
+    )
+    target_include_directories(AutoStartManagerTest PRIVATE ${CMAKE_CURRENT_SOURCE_DIR})
+    target_link_libraries(AutoStartManagerTest PRIVATE Qt6::Core Qt6::Test)
+
+    add_test(NAME AutoStartManagerTest COMMAND AutoStartManagerTest)
+endif()