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>

crates/pf-driver-proto/Cargo.toml

@@ -0,0 +1,20 @@
+# Shared host<->driver binary contract for the punktfunk pf-vdisplay virtual display.
+#
+# Deliberately self-contained (no `*.workspace = true` inheritance, no Windows deps): this crate is a
+# path dependency of BOTH the host workspace (crates/punktfunk-host) AND the out-of-workspace driver
+# workspace (packaging/windows/drivers/), so it must resolve identically from either build graph. It is
+# `no_std` (+ alloc) and platform-neutral; the GUID/LUID are plain integers each side converts to its
+# own OS type. Defining every wire struct ONCE here — with `const` size/offset asserts + bytemuck
+# round-trips — makes host<->driver ABI drift a COMPILE error instead of a silent frame/IOCTL corruption.
+[package]
+name = "pf-driver-proto"
+version = "0.0.1"
+edition = "2021"
+rust-version = "1.82"
+license = "MIT OR Apache-2.0"
+description = "Shared host<->driver binary contract for the punktfunk pf-vdisplay virtual display (control IOCTLs + IDD-push frame transport)."
+publish = false
+
+[dependencies]
+# `min_const_generics`: Pod/Zeroable for `[u8; N]` of any N (the gamepad SHM reserved tails are >32).
+bytemuck = { version = "1.19", features = ["derive", "min_const_generics"] }