feat(windows): bundle pf-vdisplay in the host installer; drop SudoVDA

Switch the Inno Setup installer's virtual-display driver from the vendored SudoVDA
C++ binary to our own all-Rust pf-vdisplay (validated streaming at 5120x1440@240).

- packaging/windows/pf-vdisplay/: vendored SIGNED driver (pf_vdisplay.dll/inf/cat +
  punktfunk-driver.cer, the same cert the gamepad drivers ship), built from
  vdisplay-driver/ via deploy-dev.ps1.
- install-pf-vdisplay.ps1 / stage-pf-vdisplay.ps1: mirror the SudoVDA scripts -
  trust cert -> gated ROOT\pf_vdisplay node via nefconc (NEVER devgen) -> pnputil
  /add-driver /install. Idempotent, best-effort (never aborts the install).
- punktfunk-host.iss + pack-host-installer.ps1: install the pf-vdisplay bundle
  under the existing installdriver task.
- Removed the vendored SudoVDA driver + install-sudovda.ps1 + stage-sudovda.ps1.
- README + windows-host.yml: SudoVDA -> pf-vdisplay.

The host's vdisplay/sudovda.rs backend is unchanged - it drives whichever driver
provides the {e5bcc234} interface, now pf-vdisplay. Live installer build/test on
the runner is the remaining step.

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

.gitea/workflows/windows-host.yml

@@ -1,6 +1,6 @@
 # Build the punktfunk Windows HOST as a signed Inno Setup installer and publish it to Gitea's generic
 # package registry, so a Windows GPU box can install the streaming host (SYSTEM service + bundled
-# SudoVDA virtual-display driver + the web management console, run by a scheduled task on a bundled
+# pf-vdisplay virtual-display driver + the web management console, run by a scheduled task on a bundled
 # bun) from one signed setup.exe. Runs on the self-hosted Windows runner
 # (host mode; scripts/ci/setup-windows-runner.ps1) — same MSVC/Windows-SDK/LLVM env as windows.yml.
 #