refactor: rename pf-vdisplay-proto -> pf-driver-proto (it spans all drivers)

The shared host<->driver ABI crate already contains more than the virtual
display: the IDD-push frame ring + control plane AND the gamepad shared-memory
layouts (XusbShm / PadShm). "pf-vdisplay-proto" was a misnomer — the name now
represents all the drivers it serves.

Mechanical rename, no behavior change:
- git mv crates/pf-vdisplay-proto -> crates/pf-driver-proto (package name +
  path-deps in the host crate and the driver workspace).
- pf_vdisplay_proto -> pf_driver_proto across host + driver Rust, both Cargo.lock
  files, the workspace members, the CI path triggers (windows-drivers.yml), and
  the docs/INF comments. The runtime Global\pfvd-* shared-object names are a
  SEPARATE contract and are deliberately untouched (host<->driver name matching).
- The pf-vdisplay DRIVER crate + its INF service name (Root\pf_vdisplay,
  UmdfService=pf_vdisplay, pf_vdisplay.dll) are unchanged — only the full
  `pf_vdisplay_proto` token was replaced, never the `pf_vdisplay` driver name.

Linux-verified: cargo test -p pf-driver-proto (const size-asserts compile) +
cargo clippy -p punktfunk-host -D warnings clean; Cargo.lock regenerated. The
driver-workspace side (path-dep + imports + its Cargo.lock) is Windows-CI-gated.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packaging/windows/drivers/pf-vdisplay/Cargo.toml

@@ -1,5 +1,5 @@
 # pf-vdisplay — the all-Rust UMDF IddCx virtual-display driver (M1 step-2 rewrite onto wdk-sys + the
-# owned pf-vdisplay-proto ABI). Replaces the vendored-binding oracle at packaging/windows/vdisplay-driver/
+# owned pf-driver-proto ABI). Replaces the vendored-binding oracle at packaging/windows/vdisplay-driver/
 # (deleted once on-glass parity is reached, per docs/windows-host-rewrite.md §14 STEP 8).
 [package]
 name = "pf-vdisplay"
@@ -23,7 +23,7 @@ wdk-build.workspace = true
 wdk.workspace = true
 wdk-sys = { workspace = true, features = ["iddcx"] }
 wdk-iddcx.workspace = true
-pf-vdisplay-proto.workspace = true
+pf-driver-proto.workspace = true
 # STEP 5: the swap-chain processor's render-side D3D11 device + worker. 0.58.0 matches the wdk-build
 # transitive `windows` already in the workspace lock (one resolved version) AND the proven oracle's
 # version, so the ported D3D/DXGI/threading calls compile verbatim.