feat(gamepad): N4 spike kit — software-devnode Steam Deck probe for Windows

The gamepad-new-types §6 go/no-go rig, ready to run the moment .173 is
back (the box is currently down, so the observation itself is still
owed): does Steam Input on Windows promote a software-devnode HID Deck
(28DE:1205), or does it need a real USB bus identity (the documented
GameInput instance-path gap — the Linux 'Interface: -1' lesson)?

- Driver: scratch device_type=3 serves the Deck identity — the captured
  38-byte controller-interface descriptor, 28DE:1205 attributes, Valve
  strings, the Deck neutral frame, and the Steam 0x83/0xAE feature
  contract (SET_FEATURE latches the command, GET_FEATURE answers it —
  attribute blob + unit serial mirroring steam_proto::feature_reply).
  Never stamped by a session. INF gains pf_steamdeck.
- Host: deck_spike_hold() + the `deck-windows-spike` subcommand — stamps
  devtype 3, spawns the devnode under VID_28DE&PID_1205, streams the
  neutral frame, prints what to observe (Steam logs/controller.txt,
  controller settings) and logs any output reports Steam writes.

Run recipe (on .173, once the updated signed driver is staged): install
driver, start Steam, `punktfunk-host.exe deck-windows-spike`, watch
controller.txt. GO -> plan a proper N4 phase (the Deck codec is already
shared); NO-GO -> document next to the Linux Interface:-1 note and keep
the SteamDeck->DualSense Windows fold.

Verified: .133 clippy -D warnings + the driver workspace cargo check
(WDK) both green; .21 clippy + 304/0 tests unaffected.

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

crates/punktfunk-host/src/main.rs

@@ -388,6 +388,19 @@ fn real_main() -> Result<()> {
             println!("switchpro-test: done");
             Ok(())
         }
+        // Windows N4 SPIKE (gamepad-new-types §6): hold a software-devnode HID Steam Deck
+        // (28DE:1205 via device_type 3) and watch whether Steam Input promotes it. Needs the
+        // updated signed driver installed + Steam running. `--seconds N` (default 120).
+        #[cfg(target_os = "windows")]
+        Some("deck-windows-spike") => {
+            let secs: u64 = args
+                .iter()
+                .skip_while(|a| *a != "--seconds")
+                .nth(1)
+                .and_then(|s| s.parse().ok())
+                .unwrap_or(120);
+            inject::dualsense_windows::deck_spike_hold(0, secs)
+        }
         // Windows: create a virtual DualSense via the UMDF driver (SwDeviceCreate per-session devnode
         // + the shared-memory channel) and hold it, pushing one fixed frame (Cross + LS-right). Drives
         // the real DualSenseWindowsManager, so it validates the device lifecycle end to end. Verify