feat(android): physical mouse + TV remote-as-pointer + keyboard hardening

Phase A — hardware mouse: new MouseForwarder routes every SOURCE_MOUSE event
while streaming. Uncaptured (default): hover/drag positions forward as absolute
cursor moves, wheel with fractional accumulation (high-res wheels), all five
buttons incl. back/forward as X1/X2; the local cursor is hidden over the stream
(TYPE_NULL pointer icon) so the host's composited cursor is the visible one.
Captured ("Capture pointer for games" setting, or Ctrl+Alt+Shift+Q live): the
OS pointer is grabbed via requestPointerCapture on the (repurposed) key-capture
view and raw relative deltas forward as mouse-look; held buttons are tracked
and flushed on capture loss/teardown, and the engaging click is swallowed
(desktop parity). Mouse clicks are intercepted before Compose so they can never
be misread as trackpad taps; a mouse back-button's FALLBACK BACK is dropped so
it can't yank the user out of the stream.

Phase B — keyboard: media/consumer keys (play/pause/next/prev/stop) now map to
their VKs instead of falling to the system; TV-remote SELECT maps to Enter.

Phase D — Android TV: RemotePointer turns a D-pad-only remote into a pointer
(Siri-remote analogue): hold SELECT ~0.8s toggles, D-pad glides the host cursor
with ramped acceleration (Choreographer-paced, diagonal-normalized), SELECT
taps click, play/pause right-clicks, holding it toggles the on-screen keyboard,
BACK leaves pointer mode; an overlay hint teaches the vocabulary.

Settings: "Capture pointer for games" + "Invert scroll direction" (applies
to the wheel and two-finger touch scrolling).

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

clients/android/kit/src/main/kotlin/io/unom/punktfunk/kit/Keymap.kt

@@ -106,6 +106,17 @@ object Keymap {
         KeyEvent.KEYCODE_DPAD_UP -> 0x26
         KeyEvent.KEYCODE_DPAD_RIGHT -> 0x27
         KeyEvent.KEYCODE_DPAD_DOWN -> 0x28
+        // TV-remote SELECT = Enter (a gamepad's press routes via SOURCE_GAMEPAD before this).
+        KeyEvent.KEYCODE_DPAD_CENTER -> 0x0D
+
+        // Consumer/media keys — forwarded to the host while streaming (volume stays local:
+        // MainActivity's pass-through list wins before the map is consulted).
+        KeyEvent.KEYCODE_MEDIA_PLAY_PAUSE,
+        KeyEvent.KEYCODE_MEDIA_PLAY,
+        KeyEvent.KEYCODE_MEDIA_PAUSE -> 0xB3 // VK_MEDIA_PLAY_PAUSE
+        KeyEvent.KEYCODE_MEDIA_NEXT -> 0xB0 // VK_MEDIA_NEXT_TRACK
+        KeyEvent.KEYCODE_MEDIA_PREVIOUS -> 0xB1 // VK_MEDIA_PREV_TRACK
+        KeyEvent.KEYCODE_MEDIA_STOP -> 0xB2 // VK_MEDIA_STOP
 
         // Modifiers (L/R-specific VKs; the host folds the generic ones onto the left variant)
         KeyEvent.KEYCODE_SHIFT_LEFT -> 0xA0