Add capture pipeline rate + latency metrics to the Video panel

The FPS readout only measured the host's own render rate, hiding capture stutter.
The Video panel now shows a "Pipeline rates" section:
- Tool render (host FPS / frametime, as before);
- hooked source: Game present (/s, from VideoShare.present_calls deltas), Hook
  publish (/s, generation deltas), and capture->display latency avg/min/max ms;
- WGC source: WGC capture (/s) from a new WindowCapture frame-arrival counter
  (game present + latency are n/a, since WGC frames aren't game-timestamped).

Latency uses a system-wide clock: protocol v11->v12 adds VideoShare.present_qpc,
stamped by the hook at publish (publish_video_frame); the host measures
now_qpc - present_qpc per newly published frame, windowed to min/avg/max each second.

Verified: present_hook_test (x64 + x86) now asserts present_qpc is stamped; full
build x64 + x86 clean; ctest x64 9/9, x86 3/3. The live rate/latency numbers need a
real game mirroring to read meaningfully; wiring validated.

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

README.md

@@ -76,14 +76,6 @@ is removed from this list once done — so the top item is always next. The
 self-verifiable tooling / UI / input items come first; the game-pipeline items that
 need a real game (and Remote Play) to fully validate come last.
 
-- **Real capture metrics + latency stats.** The current FPS readout only measures
-  how fast the host renders its own window, which hides capture stutter. Add a
-  three-line frametime/FPS graph — **game present rate** (from `VideoShare` present
-  deltas), **capture rate** (generation deltas / WGC arrivals), and **tool render
-  rate** — plus a **capture→display latency** stat: stamp each published frame with
-  a `QueryPerformanceCounter` value in `VideoShare`, and the host reports
-  `host-present QPC − game-present QPC` (min/avg/max ms) for the matched frame. QPC
-  is system-wide, so the two processes' timestamps compare directly.
 - **DX12 hooked capture (Spider-Man: Miles Morales).** Miles Morales is D3D12, so
   the Present hook fires but `GetBuffer(0)` as `ID3D11Texture2D` fails (the
   backbuffer is an `ID3D12Resource`) and the hook idles; WGC works but stutters. Add