feat(host/windows): seal the host↔driver channels (frame + gamepad, proto v2)

Frame ring (pf-vdisplay) and both gamepad SHM channels move off named Global\
objects (openable by any sibling LocalService) to UNNAMED sections/events whose
handles the host DuplicateHandles into the driver's verified WUDFHost with least
access — frame delivery over the SYSTEM+admins-only IOCTL_SET_FRAME_CHANNEL,
pads over a 32-byte named bootstrap mailbox (pid + handle value only, DoS-bounded;
HID minidrivers have no control device). Driver-validated pad_index kills
cross-pad redirects; v1↔v2 mixes fail closed with diagnosis logs on both sides.
Sibling-LocalService denial proven empirically (design/idd-push-security.md,
design/gamepad-channel-sealing.md).

Driver-side raw ops now live behind pf-umdf-util (checked shm accessors, the
forbid(unsafe_code) ChannelClient state machine, WDF request tokens) — the pad
drivers' logic is 100% safe Rust; whole drivers workspace clippy-gated in CI.

driver install --gamepad now sweeps SWD\punktfunk phantom devnodes: a re-created
SwDevice REVIVES the old devnode with its previously-bound driver (never
re-ranks), so an upgrade otherwise leaves the old driver serving — or, across
the v1→v2 fence, a dead pad (found live on the RTX box).

On-glass validated on the RTX 4090 box: frame path 7007 frames p50 2.06 ms
cross-machine; DualSense + XUSB "sealed pad channel mapped"/proto=2 attach via
both the test harness and a real streaming session; phantom-sweep repro.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

packaging/windows/drivers/pf-vdisplay/src/lib.rs

@@ -10,9 +10,12 @@
 
 #![allow(non_snake_case, clippy::missing_safety_doc)]
 // P0 lint (audit §8): an unsafe op inside an `unsafe fn` must be in an explicit `unsafe {}` block, so the
-// fn-level `unsafe` never silently blesses the whole body. (The per-site `// SAFETY:` discipline already
-// landed in STEP 8.)
+// fn-level `unsafe` never silently blesses the whole body, AND every `unsafe {}` must carry a `// SAFETY:`
+// proof. An IddCx display driver is inherently FFI-bound (D3D11 / IddCx DDIs / cross-process shared
+// textures), so it can't be unsafe-FREE the way the gamepad drivers now are (their logic moved onto the
+// safe `pf_umdf_util` layer); these gates make it unsafe-AUDITED instead, and stop it regressing.
 #![deny(unsafe_op_in_unsafe_fn)]
+#![deny(clippy::undocumented_unsafe_blocks)]
 
 #[macro_use]
 mod log;