feat(windows): pf-vdisplay IDD-push — HDR + pipelined zero-copy capture

HDR (display-driven, matching the WGC path):
- CTA-861.3 HDR EDID (BT.2020 primaries + HDR Static Metadata block) so Windows
  offers "Use HDR" on the virtual display. The host FOLLOWS the display's live
  advanced-color state, recreating the shared ring at the matching format
  (FP16 in HDR / BGRA in SDR) on a toggle — no freeze.
- Always emit Main10/BT.2020-PQ Rgb10a2 while the display is HDR; the client
  auto-detects PQ from the HEVC VUI (clients under-report VIDEO_CAP_10BIT).
  Generic HDR10 mastering SEI on every IDR.
- Generation-tagged `latest` (gen<<40|seq<<8|slot) + driver `is_stale` re-attach
  kill the toggle-time garbage frame and any stale-ring read.

Perf:
- Pipeline the encode loop (Capturer::pipeline_depth; IDD-push = 2): submit N+1
  before polling N so the convert/copy on the 3D engine overlaps the NVENC encode
  of N on the ASIC. PUNKTFUNK_IDD_DEPTH overrides (1 = synchronous).
- Rotating host output ring (OUT_RING) so the in-flight encode and the next
  convert never touch the same texture.
- HDR converts directly from the keyed-mutex slot's SRV into the output ring
  (drops the redundant slot->fp16 scratch copy); SDR copies the BGRA slot in.
  The slot mutex is held only across the convert/copy, not the encode.
  RING_LEN 3->6 for publish headroom.
- Capture-health diagnostic: new_fps vs repeat_fps under PUNKTFUNK_PERF (a low
  new_fps at a high send rate means the source isn't compositing, not an encode
  stall).

Validated live on the RTX box: 5120x1440@240 HDR streams; driver composes
~180 new fps, encode 240 fps @ ~4.3 ms p50.

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

packaging/windows/README.md

@@ -55,10 +55,11 @@ read it from `%ProgramData%\punktfunk\web-password`.
 
 ## Prerequisites on the target box
 
-- An **NVIDIA GPU + driver** — the installer's exe is built `--features nvenc` and load-depends on the
-  driver's `nvEncodeAPI64.dll`.
-- **ViGEmBus** (optional) for virtual gamepads — still a manual prerequisite (not bundled yet):
-  <https://github.com/nefarius/ViGEmBus/releases>.
+- A **GPU for hardware encode**: an NVIDIA GPU + driver (NVENC), or an AMD/Intel GPU (AMF/QSV) — the
+  exe is built `--features nvenc,amf-qsv`. Software H.264 is the GPU-less fallback.
+- **Virtual gamepads need no prerequisite.** The DualSense / DualShock 4 / Xbox 360 (XUSB) UMDF drivers
+  are **bundled** in the installer (the *Install the virtual gamepad drivers* task) and
+  `pnputil`-installed. **ViGEmBus is no longer used.**
 
 ## Files here