Vulkan capture: preserve the game's sync mode, drop the capture throttle

The capture must never change vsync, and must not frame-limit itself.

- Removed the ~150 Hz capture throttle from VkCapture. It was wrong: vsync already
  paces capture (a 144 Hz FIFO game presents 144x/s, so we mirror 144x/s). The only
  limiter left is ring backpressure (skip a frame if the reaper is behind), which is
  correctness, not a cap, and never touches the game's present thread or sync mode.
- The layer/hook already pass VkSwapchainCreateInfoKHR straight through, so the
  present mode (= the sync mode) is untouched. Added a presentMode log to prove it.

Measured on Sphere Spectacle (direct launch, layer attached): presentMode=2 (FIFO),
steady 144.0 fps, and with the throttle gone the mirror now tracks it at 144/s
(was capped ~130). The earlier 400-600 fps reading was a direct-launch artifact --
a non-foreground windowed FIFO app isn't throttled by DWM -- not the layer, and not
the case through Steam (144). vk_validate now states the mirror follows the present
rate (no throttle) and still asserts a present-rate floor.

Full suite 21/21.

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

hook/src/vk_capture.cpp

@@ -8,17 +8,6 @@
 namespace coop::hook
 {
 
-namespace
-{
-double now_ms()
-{
-	LARGE_INTEGER f, c;
-	QueryPerformanceFrequency(&f);
-	QueryPerformanceCounter(&c);
-	return 1000.0 * static_cast<double>(c.QuadPart) / static_cast<double>(f.QuadPart);
-}
-} // namespace
-
 VkCapture::~VkCapture()
 {
 	shutdown();
@@ -340,11 +329,10 @@ bool VkCapture::present(VkImage image, VkFormat fmt, std::uint32_t w, std::uint3
 	{
 		return false;
 	}
-	const double t = now_ms();
-	if (t - m_last_submit_ms < kMinCaptureIntervalMs)
-	{
-		return false; // throttle: mirror at ~150 Hz, not the game's (possibly 400+) present rate
-	}
+	// No time-based throttle here: capture follows the game's present rate, which vsync paces (if the
+	// game vsyncs at 144 Hz it presents 144x/s, so we capture 144x/s). The only limiter is ring
+	// backpressure below -- if the reaper can't keep up we skip a frame rather than block the game --
+	// which is correctness, not a frame cap (it never stalls the present thread or touches sync mode).
 	// Pick a slot whose previous capture the reaper has finished. None free -> the reaper is behind,
 	// so skip this frame (the game keeps its rate; the mirror just drops a frame).
 	int idx = -1;
@@ -408,7 +396,6 @@ bool VkCapture::present(VkImage image, VkFormat fmt, std::uint32_t w, std::uint3
 	{
 		return false;
 	}
-	m_last_submit_ms = t;
 	s.w = w;
 	s.h = h;
 	s.fmt = fmt;

hook/src/vk_capture.hpp

@@ -146,11 +146,6 @@ private:
 	VkCommandPool m_pool = VK_NULL_HANDLE;
 	Slot m_slots[kSlots];
 	int m_next = 0;
-	// Cap capture to ~150 Hz: a guest stream is at most the host's refresh (usually 60, at most 144),
-	// so mirroring every present of an uncapped 400+ FPS game is pure wasted reaper CPU. Throttling
-	// here -- not on the game -- keeps the mirror smooth while freeing the cores the game wants.
-	static constexpr double kMinCaptureIntervalMs = 1000.0 / 150.0;
-	double m_last_submit_ms = 0.0;
 
 	// --- D3D11 shared texture (reaper thread only) ---
 	ID3D11Device* m_d3d = nullptr;