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/Cargo.toml

@@ -4,7 +4,7 @@
 #
 # Separate from the main cargo workspace (own [workspace] root) because driver crates are cdylibs built
 # with the WDK toolchain (cargo-wdk / wdk-build) on Windows only. Path-deps the shared ABI crate
-# crates/pf-vdisplay-proto from the main tree.
+# crates/pf-driver-proto from the main tree.
 [workspace]
 resolver = "2"
 members = ["wdk-probe", "wdk-iddcx", "pf-vdisplay"]
@@ -20,7 +20,7 @@ wdk = "0.4.1"
 wdk-sys = "0.5.1"
 wdk-build = "0.5.1"
 wdk-iddcx = { path = "wdk-iddcx" }
-pf-vdisplay-proto = { path = "../../../crates/pf-vdisplay-proto" }
+pf-driver-proto = { path = "../../../crates/pf-driver-proto" }
 
 # Vendored windows-drivers-rs 0.5.1 (the published, self-contained crates) + an added `iddcx`
 # ApiSubset (M1 — bindgens iddcx/1.10/IddCx.h reusing wdk_default for WDF type-identity). Redirect ALL