docs(windows-host): SCM event redesign done + runtime-validated (D2 complete)

The service.rs STOP/SESSION events are now OnceLock<OwnedHandle> (61c02e6) — the
last host-side raw-handle smuggle retired. Runtime-validated on the RTX box: swap
in, sc start -> RUNNING, sc stop -> clean STOPPED in ~1s, original restored. D2
(OwnedHandle/RAII rollout) is complete; only the deferred host P0 lints remain in
Goal 3.

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

docs/windows-host-rewrite.md

@@ -34,7 +34,7 @@ which kept the live-validated host working at every step. The driver, by contras
 |---|---|---|
 | **Goal 1** — clean, layered host architecture | ✅ **DONE** | `config.rs` (`HostConfig`), `session_plan.rs` (`SessionPlan`), `SessionContext`, `windows/`+`linux/` confinement (`38c68c3`), `VirtualDisplayManager` (§2.5), `EncoderCaps` (`0ccd0fe`) |
 | **Goal 2** — drop every trace of SudoVDA | ✅ **DONE** | reach-in decoupled (F1: `d638a93`/`e60cda3` → `win_adapter`/`win_display`), then the `sudovda.rs` backend + the dual-backend select **deleted** (this branch) — pf-vdisplay is the sole Windows virtual-display backend |
-| **Goal 3** — minimize `unsafe` + P0 lints | 🟡 **PARTIAL** (**box-validated**) | driver `deny(unsafe_op_in_unsafe_fn)` (`a755d6e`); **`OwnedHandle`/RAII rollout** — `idd_push.rs` (`011607e`, view-leak fix) + `service.rs` child/job (`4c95ba7`) + the 3 gamepad backends via shared `gamepad_raii.rs` (`e5c2b4e`) + the IDD-push `KeyedMutexGuard` hot loop (`6585643`); **driver `pod_init!`** (`bf57704`, 27→1). **On-glass clean: host clippy `-D warnings` + driver build** (RTX box; `bd05bc8` fixed 11 lints the gate surfaced). Remaining: host-crate P0 lints (deferred — churn>value), the `service.rs` SCM-handler event smuggling (deliberately left) |
+| **Goal 3** — minimize `unsafe` + P0 lints | 🟡 **PARTIAL** (**box-validated**) | driver `deny(unsafe_op_in_unsafe_fn)` (`a755d6e`); **`OwnedHandle`/RAII rollout** — `idd_push.rs` (`011607e`, view-leak fix) + `service.rs` child/job (`4c95ba7`) + the 3 gamepad backends via shared `gamepad_raii.rs` (`e5c2b4e`) + the IDD-push `KeyedMutexGuard` hot loop (`6585643`) + the **SCM STOP/SESSION events** → `OnceLock<OwnedHandle>` (`61c02e6`, runtime-validated: clean ~1 s `sc stop`); **driver `pod_init!`** (`bf57704`, 27→1). **On-glass clean: host clippy `-D warnings` + driver build** (RTX box; `bd05bc8` fixed 11 lints the gate surfaced). The host-side raw-handle smuggling is fully retired; only host-crate P0 lints remain (deferred — churn>value) |
 | **M0** — proto ABI + driver toolchain + `/INTEGRITYCHECK` + `iddcx` | ✅ **DONE** | `pf-driver-proto`; vendored `windows-drivers-rs` 0.5.1; `clear-force-integrity.ps1`; CI-green |
 | **M1** — new IddCx driver, first light + HDR | ✅ **DONE (on-glass)** | STEP 0–8 (`d7a9fbf`…`cd59151`); HDR live ("Mac connects WITH HDR", `6399d28`) |
 | **M2** — IDD-push capture + NVENC, glass-to-glass | ✅ **DONE (on-glass)** | 5120×1440@240 HDR zero-copy; integrated into the host path |
@@ -226,14 +226,16 @@ These are expensive empirical wins; keep them intact when touching the code:
    `unsafe fn`s need an inner `unsafe {}`). Stage it **per-module, Linux-first** (item-level `#[deny]` on
    `linux/zerocopy/cuda.rs`/`egl.rs`, `encode/linux/vaapi.rs` — locally verifiable), then the Windows
    modules (CI-gated), then promote to crate-level. The driver already has the deny.
-5. **D2 — `OwnedHandle` / RAII rollout.** ✅ **done** — `capture/windows/idd_push.rs` (`011607e`: a
+5. **D2 — `OwnedHandle` / RAII rollout.** ✅ **DONE (complete).** `capture/windows/idd_push.rs` (`011607e`:
-   `MappedSection` RAII for the mapping handle **+** the leaked `MapViewOfFile` view, + `OwnedHandle` for the
+   a `MappedSection` RAII for the mapping handle **+** the leaked `MapViewOfFile` view, + `OwnedHandle` for
-   event / ring-slot shared handles); `windows/service.rs` (`4c95ba7`: the child process/thread + Job
+   the event / ring-slot shared handles); `windows/service.rs` (`4c95ba7`: the child process/thread + Job
-   handles, ~9 `CloseHandle` deleted); and the **three gamepad backends** (`e5c2b4e`: a shared
+   handles, ~9 `CloseHandle` deleted); the **three gamepad backends** (`e5c2b4e`: a shared
    `inject/windows/gamepad_raii.rs` — `Shm` for the section+view, `SwDevice` for the devnode — replacing the
-   duplicated `create_shm_section` + three hand-written `Drop`s). **Remaining (deliberately left):** the
+   duplicated `create_shm_section` + three hand-written `Drop`s); and the **SCM STOP/SESSION events**
-   `service.rs` `AtomicIsize` STOP/SESSION events — smuggled into the C SCM handler, a separate riskier
+   (`61c02e6`: `AtomicIsize` raw-`isize` smuggle → `OnceLock<OwnedHandle>` the capture-free C handler reads,
-   redesign. `manager.rs`/`pf_vdisplay.rs` already used the pattern.
+   owned for the process lifetime — also closes a latent close-then-signal window). **Runtime-validated on
+   the RTX box**: swapped in, `sc start` → RUNNING, `sc stop` → clean STOPPED in ~1 s (not a timeout-kill),
+   original restored. `manager.rs`/`pf_vdisplay.rs` already used the pattern.
 6. **Hot-loop `KeyedMutexGuard` ✅ done** (`6585643`) — the IDD-push consume loop's hand-written
    `AcquireSync`/`ReleaseSync` (with its "don't `?`-return between them or you leak the lock + stall the
    driver" caveat) is now a RAII guard scoped to the convert/copy block: same release point (latency