Deduplicate the hook DLL and scrub history from its comments

Consolidate four copies of the keyed-mutex shared-texture setup
(present/opengl/d3d9/vk_capture) into one RAII SharedVideoTexture,
two copies of find_main_window into find_window.hpp, audio_hook's
hand-rolled detour guard into the shared DetourGate, the duplicated
vtable_method into vtable_hook.hpp, and the near-identical
Present/Present1 and SwapBuffers/wglSwapBuffers detour pairs into one
shared body each. The vk_layer and vk_capture_perf_test targets now
compile debug_log.cpp since the shared texture code logs.

Comments no longer narrate the past: drop stress-test/game anecdotes,
"used to"/"the old model" phrasing, plan-step labels, and pointers to
docs that do not exist; fix present_hook.hpp/opengl_hook.hpp claims
that predate the D3D12/D3D9/Vulkan backends. Net -266 lines, no
behavior change (full x64 + x86 suites pass, including the mock-game
hook/unhook storm).

vk_layer/CMakeLists.txt

@@ -7,7 +7,8 @@ coop_require_submodule("Vulkan-Headers" "third_party/Vulkan-Headers/include/vulk
 
 add_library(coop_vk_layer SHARED
 	coop_vk_layer.cpp
-	${CMAKE_SOURCE_DIR}/hook/src/vk_capture.cpp) # shared off-present-thread read-back (also used by vk_hook)
+	${CMAKE_SOURCE_DIR}/hook/src/vk_capture.cpp  # shared off-present-thread read-back (also used by vk_hook)
+	${CMAKE_SOURCE_DIR}/hook/src/debug_log.cpp)  # logging used by the shared capture code
 
 target_include_directories(coop_vk_layer PRIVATE
 	${CMAKE_SOURCE_DIR}/hook/src                              # ipc_client.hpp (reused IPC client)