feat(windows-drivers): pf-vdisplay STEP 0 scaffold + std-under-UMDF link gate

M1 step 2 begins. Add the wdk-iddcx (lib, re-exports wdk_sys::iddcx) + pf-vdisplay
(cdylib) workspace members. pf-vdisplay STEP 0 = DriverEntry + WdfDeviceCreate
skeleton + a #[used] _std_link_gate forcing std::thread + OwnedHandle to link, so
the build proves the std surface resolves under the wdk-build UMDF link settings
(kernel32 is /NODEFAULTLIB - std must come via OneCoreUAP). If std fails to link
here, the SwapChainProcessor worker-thread design needs a CreateThread shim before
any callback work (port-plan critique gap #9).

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

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

@@ -0,0 +1,26 @@
+# 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/
+# (deleted once on-glass parity is reached, per docs/windows-host-rewrite.md §14 STEP 8).
+[package]
+name = "pf-vdisplay"
+edition.workspace = true
+version.workspace = true
+license.workspace = true
+publish = false
+
+[package.metadata.wdk.driver-model]
+driver-type = "UMDF"
+umdf-version-major = 2
+target-umdf-version-minor = 31
+
+[lib]
+crate-type = ["cdylib"]
+
+[build-dependencies]
+wdk-build.workspace = true
+
+[dependencies]
+wdk.workspace = true
+wdk-sys = { workspace = true, features = ["iddcx"] }
+wdk-iddcx.workspace = true
+pf-vdisplay-proto.workspace = true