feat(core,host,android): Steam Controller 2 as-is passthrough to Linux hosts

The 2026 Steam Controller (Valve "Ibex" / SDL "Triton") captured on an
Android client is passed through AS-IS: the host presents a virtual pad
with the real wired identity (28DE:1302) and mirrors the physical pad's
raw HID reports, so Steam on the host drives it over hidraw exactly like
the real thing — trackpads, gyro, paddles, and its rumble/settings writes
flow back onto the physical controller. Protocol ground truth: SDL's
Valve-maintained SDL_hidapi_steam_triton.c + steam/controller_structs.h.

Core:
- GamepadPref::SteamController2 (wire byte 9; names steamcontroller2/
  sc2/ibex) + PUNKTFUNK_GAMEPAD_STEAMCONTROLLER2 in the C ABI.
- Raw HID planes: RichInput::HidReport (0xCC/0x04, client→host input
  reports verbatim, Copy fixed-64 body) and HidOutput::HidRaw (0xCD/0x05,
  host→client feature/output writes for replay). Best-effort is sound by
  the device protocol's own design (rumble re-sent every ~40 ms, settings
  every ~3 s — losses self-heal); HidRaw bypasses hidout dedup for
  exactly that reason.

Host (Linux):
- triton_proto.rs + steam_controller2.rs: Triton2Manager UHID backend —
  no kernel driver binds the PID (hidraw only; Steam Input is the
  consumer), raw mirroring with a typed-fallback 0x42 synthesizer until
  the first raw report, SET_REPORT ack + raw forward, canned GET_REPORT
  serial reply, rumble also parsed onto the universal 0xCA plane (phone
  mirror). Rides the uhid + 28DE-conflict degrades; UHID promotion by
  Steam is flagged in the creation log (usbip transport is the known
  follow-up if Steam ignores Interface:-1 devices for Triton too).

Android:
- Sc2UsbLink (wired/Puck: vendor-interface claim detaches the OS driver,
  interrupt read loop, lizard-off on the watchdog cadence, raw replay via
  interrupt-OUT / SET_REPORT with hidapi report-id framing) and Sc2BleLink
  (Valve vendor GATT service, notify subscribe machine, 0x45 re-framing,
  HIGH connection priority).
- Sc2Capture orchestrator: raw plane + typed mirror (exit chord + host
  degrade paths keep working) on a GamepadRouter external slot; raw
  return path via GamepadFeedback.onHidRaw.
- nativeSendPadHidReport JNI (direct ByteBuffer, no per-report copy),
  hidout raw decode, usb-host/BLUETOOTH_CONNECT manifest bits, opt-out
  settings toggle, StreamScreen engagement incl. the USB permission flow.

Verified: core 149 + host 312 tests green on Linux (.21), on-box uhid
smoke creates/mirrors/tears down the virtual 28DE:1302, C ABI harness
round-trips, Android compileDebugKotlin green. On-glass with the real
controller owed.

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

crates/punktfunk-host/src/punktfunk1.rs

@@ -1869,6 +1869,8 @@ struct Pads {
     switchpro: Option<crate::inject::switch_pro::SwitchProManager>,
     #[cfg(target_os = "linux")]
     steamctrl: Option<crate::inject::steam_controller::SteamCtrlManager>,
+    #[cfg(target_os = "linux")]
+    steamctrl2: Option<crate::inject::steam_controller2::Triton2Manager>,
     #[cfg(target_os = "windows")]
     dualsense_win: Option<crate::inject::dualsense_windows::DualSenseWindowsManager>,
     #[cfg(target_os = "windows")]
@@ -1906,6 +1908,8 @@ impl Pads {
             switchpro: None,
             #[cfg(target_os = "linux")]
             steamctrl: None,
+            #[cfg(target_os = "linux")]
+            steamctrl2: None,
             #[cfg(target_os = "windows")]
             dualsense_win: None,
             #[cfg(target_os = "windows")]
@@ -1989,6 +1993,11 @@ impl Pads {
                 .get_or_insert_with(crate::inject::steam_controller::SteamCtrlManager::new)
                 .handle(ev),
             #[cfg(target_os = "linux")]
+            GamepadPref::SteamController2 => self
+                .steamctrl2
+                .get_or_insert_with(crate::inject::steam_controller2::Triton2Manager::new)
+                .handle(ev),
+            #[cfg(target_os = "linux")]
             GamepadPref::XboxOne => self
                 .xboxone
                 .get_or_insert_with(|| {
@@ -2036,7 +2045,8 @@ impl Pads {
         let idx = match rich {
             RichInput::Touchpad { pad, .. }
             | RichInput::Motion { pad, .. }
-            | RichInput::TouchpadEx { pad, .. } => pad as usize,
+            | RichInput::TouchpadEx { pad, .. }
+            | RichInput::HidReport { pad, .. } => pad as usize,
         };
         // Route to the manager that actually owns the device (falling back to the declared kind
         // before the first frame builds it), so a pad's touchpad/motion never lands on the wrong
@@ -2085,6 +2095,12 @@ impl Pads {
                     m.apply_rich(rich)
                 }
             }
+            #[cfg(target_os = "linux")]
+            GamepadPref::SteamController2 => {
+                if let Some(m) = &mut self.steamctrl2 {
+                    m.apply_rich(rich)
+                }
+            }
             #[cfg(target_os = "windows")]
             GamepadPref::DualSense => {
                 if let Some(m) = &mut self.dualsense_win {
@@ -2148,6 +2164,9 @@ impl Pads {
             if let Some(m) = &mut self.steamctrl {
                 m.pump(&mut rumble, &mut hidout);
             }
+            if let Some(m) = &mut self.steamctrl2 {
+                m.pump(&mut rumble, &mut hidout);
+            }
         }
         #[cfg(target_os = "windows")]
         {
@@ -2192,6 +2211,9 @@ impl Pads {
             if let Some(m) = &mut self.steamctrl {
                 m.heartbeat(gap);
             }
+            if let Some(m) = &mut self.steamctrl2 {
+                m.heartbeat(gap);
+            }
         }
         #[cfg(target_os = "windows")]
         {
@@ -2903,6 +2925,11 @@ fn pick_gamepad(pref: GamepadPref, env: Option<&str>, linux: bool, windows: bool
         // Switch Pro: Linux UHID hid-nintendo (≥ 5.16) — correct Nintendo glyphs + positional
         // layout + gyro + HD rumble. No Windows backend; folds to Xbox360 there.
         GamepadPref::SwitchPro if linux => GamepadPref::SwitchPro,
+        // New Steam Controller (2026, `28DE:1302`): passed through as-is on Linux — the Triton
+        // UHID backend mirrors the client's raw reports under the real identity and Steam on
+        // the host drives it over hidraw (no kernel driver binds the PID; Steam Input is the
+        // consumer). No Windows backend; folds to Xbox360 there.
+        GamepadPref::SteamController2 if linux => GamepadPref::SteamController2,
         _ => GamepadPref::Xbox360,
     }
 }
@@ -2920,6 +2947,7 @@ fn degrade_if_no_uhid(chosen: GamepadPref) -> GamepadPref {
             | GamepadPref::DualShock4
             | GamepadPref::SteamDeck
             | GamepadPref::SteamController
+            | GamepadPref::SteamController2
             | GamepadPref::SwitchPro
     );
     if needs_uhid
@@ -2985,7 +3013,7 @@ fn physical_steam_controller_present() -> bool {
 fn degrade_steam_on_conflict(chosen: GamepadPref) -> GamepadPref {
     if !matches!(
         chosen,
-        GamepadPref::SteamDeck | GamepadPref::SteamController
+        GamepadPref::SteamDeck | GamepadPref::SteamController | GamepadPref::SteamController2
     ) {
         return chosen;
     }
@@ -5622,6 +5650,22 @@ mod tests {
         assert_eq!(pick_gamepad(Auto, Some("switch"), true, false), SwitchPro);
         assert_eq!(pick_gamepad(SwitchPro, None, false, true), Xbox360);
         assert_eq!(pick_gamepad(SwitchPro, None, false, false), Xbox360);
+        // New Steam Controller (as-is Triton passthrough): native on Linux (UHID, Steam-driven);
+        // Xbox360 on Windows and elsewhere.
+        assert_eq!(
+            pick_gamepad(SteamController2, None, true, false),
+            SteamController2
+        );
+        assert_eq!(
+            pick_gamepad(Auto, Some("sc2"), true, false),
+            SteamController2
+        );
+        assert_eq!(
+            pick_gamepad(Auto, Some("ibex"), true, false),
+            SteamController2
+        );
+        assert_eq!(pick_gamepad(SteamController2, None, false, true), Xbox360);
+        assert_eq!(pick_gamepad(SteamController2, None, false, false), Xbox360);
     }
 
     #[test]