feat(android): DualSense host->client feedback — rumble + lightbar/LEDs/triggers

M4 Android stage 1 (DualSense feedback, host->client). Two Kotlin poll threads drain the
connector's rumble (0xCA) + HID-output (0xCD) planes via blocking native pulls and render
in Kotlin (Option B — no JNI upcalls, Android APIs stay in Kotlin).

- crates/punktfunk-android: feedback.rs — nativeNextRumble (returns (low<<16)|high, or -1)
  + nativeNextHidout (writes [kind][fields] into a caller's direct ByteBuffer). Ungated; no
  new Cargo deps (next_rumble/next_hidout are on the quic feature already).
- clients/android: GamepadFeedback.kt — rumble -> VibratorManager (two-motor amplitude),
  HID Led -> lightbar + PlayerLeds -> player LED via LightsManager (API 33+), adaptive
  triggers parsed + logged (no public Android API); resolves the connected pad, emulator ->
  logged no-op. Started/stopped in the StreamScreen lifecycle (stop + join before nativeClose).

Verified live (emulator -> synthetic host, PUNKTFUNK_TEST_FEEDBACK=1): client received +
decoded the full burst -- rumble low=16384 high=32768, Led r=10 g=20 b=30, PlayerLeds bits=4
player=1, Trigger which=1 mode=0x21 -- matching the host hook exactly. Rendering is a logged
no-op on the emulator (no controller); real haptics/lightbar/player-LED need a physical pad.
Deferred (need a physical DualSense + device enumeration): client->host rich input
(touchpad/motion send_rich_input) and DualSense controller-type negotiation.

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

clients/android/app/src/main/kotlin/io/unom/punktfunk/MainActivity.kt

@@ -43,6 +43,7 @@ import androidx.compose.ui.text.input.KeyboardType
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.viewinterop.AndroidView
 import io.unom.punktfunk.kit.Gamepad
+import io.unom.punktfunk.kit.GamepadFeedback
 import io.unom.punktfunk.kit.Keymap
 import io.unom.punktfunk.kit.NativeBridge
 import kotlin.math.abs
@@ -205,7 +206,10 @@ private fun StreamScreen(handle: Long, onDisconnect: () -> Unit) {
         window?.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
         activity?.streamHandle = handle // route hardware keys to this session
         activity?.axisMapper = Gamepad.AxisMapper(handle) // route joystick axes
+        // Host→client feedback (rumble + DualSense lightbar/LEDs); poll threads stopped before close.
+        val feedback = GamepadFeedback(handle).also { it.start() }
         onDispose {
+            feedback.stop() // stop + join the poll threads BEFORE nativeClose frees the handle
             activity?.axisMapper?.reset() // release-all so nothing sticks on the host
             activity?.axisMapper = null
             activity?.streamHandle = 0L