Add focus_spoof_test (and close the dedicated-hook-tests item)

focus_spoof_test plays game + host: it creates a top-level window (which
find_main_window picks up), installs the spoof, and checks that
GetForegroundWindow / GetActiveWindow / GetFocus now report that window, that the
status flag flips on install and off on removal, and that a ClipCursor request is
swallowed while cursor release is the default. Skips if the window can't be
enumerated.

With this and d3d9_hook_test, the dedicated-hook-tests item is done. vk_hook's
present path is intentionally not given a separate in-process test: it's exercised
end to end by mock_game_test's vk-inject path ("hook captured Vulkan present
calls"), and the off-thread VkCapture it drives has vk_capture_perf_test -- a
standalone in-process Vulkan swapchain harness would just duplicate that at high
cost.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/CMakeLists.txt

@@ -268,6 +268,21 @@ target_link_libraries(d3d9_hook_test PRIVATE
 	dxgi)
 add_test(NAME d3d9_hook_test COMMAND d3d9_hook_test)
 
+# In-process self-test for the focus-spoof subsystem: installs the spoof on the test's own top-level
+# window and checks the focus-query APIs report it foreground/active/focused, that removal restores
+# them, and that a ClipCursor request is swallowed while cursor release is active.
+add_executable(focus_spoof_test
+	focus_spoof_test.cpp
+	${CMAKE_SOURCE_DIR}/hook/src/focus_spoof.cpp
+	${CMAKE_SOURCE_DIR}/hook/src/debug_log.cpp
+	${CMAKE_SOURCE_DIR}/hook/src/hook_registry.cpp)
+target_include_directories(focus_spoof_test PRIVATE ${CMAKE_SOURCE_DIR}/hook/src)
+target_link_libraries(focus_spoof_test PRIVATE
+	coop_common
+	safetyhook::safetyhook
+	user32)
+add_test(NAME focus_spoof_test COMMAND focus_spoof_test)
+
 # Comprehensive capture/audio/hook stress test against coop_mock_game: launches the
 # animated, frame-numbered A/V game, injects coop_hook.dll, decodes captured frame
 # numbers (DX11 + DX12) to assert a monotonic/advancing mirror, checks audio capture, and
@@ -386,6 +401,7 @@ coop_output_subdir(tests
 	present_hook_test
 	dx12_present_hook_test
 	d3d9_hook_test
+	focus_spoof_test
 	opengl_hook_test
 	mock_game_test
 	audio_verify_test