fix(fmt) + feat(gamepad): CI-matching rustfmt everywhere, enforced by repo git hooks; N4 spike flips to GO via MI_02

Three things that belong together:

1. rustfmt the gamepad-new-types host files ci.yml's `cargo fmt --all
   --check` gate flags (the .21/.133 verify recipes ran clippy+tests
   but never fmt — the same class of miss as 69f30f30).

2. Enforce it at the source: scripts/git-hooks/{pre-commit,pre-push}
   run the exact CI fmt gates (main workspace + the shipped-driver
   crates of the UMDF workspace); CONTRIBUTING documents the one-time
   `git config core.hooksPath scripts/git-hooks`. pre-push is the
   enforcement point (plumbing commits bypass pre-commit).

3. N4 follow-up — the spike verdict FLIPS TO GO: SwDeviceProfile grows
   `usb_mi`, synthesizing `&MI_02` into the Deck spike's USB hardware
   ids. hidclass mirrors the parent's USB tokens into the HID child's
   hardware ids, and hidapi/SDL/Steam parse `MI_` as bInterfaceNumber
   (defaulting to 0 when absent — the exact gate the first run hit:
   Steam wants the Deck controller on interface 2). Re-run live on
   .173: Steam logs `Interface: 2`, then `!! Steam controller device
   opened`, `Steam Controller reserving XInput slot 0`, and activates
   a mapping — full Steam Input promotion of the software-devnode
   Deck, no driver change needed. The PS identities pass
   `usb_mi: None` (real single-interface devices carry no MI_ token).
   A proper Windows-Deck backend phase is now justified; planned
   separately.

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

crates/punktfunk-host/src/inject/proto/switch_proto.rs

@@ -486,7 +486,7 @@ mod tests {
     fn pack12_layout() {
         assert_eq!(pack12(0x578, 0x578), [0x78, 0x85, 0x57]); // 1400/1400 (the cal pair)
         assert_eq!(pack12(0x800, 0x800), [0x00, 0x08, 0x80]); // 2048/2048 (the center pair)
-        // Extract back: a = b0 | (b1 & 0xF) << 8; b = (b1 >> 4) | b2 << 4.
+                                                              // Extract back: a = b0 | (b1 & 0xF) << 8; b = (b1 >> 4) | b2 << 4.
         let p = pack12(0xABC, 0x123);
         let a = p[0] as u16 | ((p[1] as u16 & 0xF) << 8);
         let b = ((p[1] as u16) >> 4) | ((p[2] as u16) << 4);