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/pf_vdisplay.inx

@@ -42,8 +42,10 @@ AddReg=pf_vdisplay_HardwareDeviceSettings
 [pf_vdisplay_HardwareDeviceSettings]
 HKR, , "UpperFilters", %REG_MULTI_SZ%, "IndirectKmd"
 HKR, "WUDF", "DeviceGroupId", %REG_SZ%, "pfVDisplayGroup"
-; Let the host (LocalSystem service) + admins open the control device for the ADD/REMOVE/PING IOCTLs.
-HKR, , "Security", , "D:P(A;;GA;;;SY)(A;;GA;;;BA)(A;;GRGW;;;WD)"
+; Only the host (LocalSystem service) + admins may open the control device. Deliberately NO Everyone
+; ACE (SudoVDA ships one for its user-mode host): the control plane creates/removes monitors and
+; bootstraps the sealed frame channel (IOCTL_SET_FRAME_CHANNEL), so it is not for unprivileged callers.
+HKR, , "Security", , "D:P(A;;GA;;;SY)(A;;GA;;;BA)"
 
 [pf_vdisplay_Install.NT.Services]
 AddService=WUDFRd,0x000001fa,WUDFRD_ServiceInstall