fix(android): harden the receiver after the review pass

- SignalingServer.send() never throws: a broken signaling connection
  drops the peer instead of killing the RTP reader thread via requestPli()
- H264Decoder: assign the codec before configure/start (no orphaned
  instance on failure); feed() reports input-queue timeouts so the
  pipeline requests a keyframe instead of dropping the frame silently
- Park offers that arrive without a surface as pendingOffer and configure
  on attachSurface(): a codec configured without a surface can never take
  one (setOutputSurface refuses it); the late configure sends a PLI
- Forget destroyed surfaces (onSurfaceTextureDestroyed -> detachSurface)
- Show the status overlay again on later messages
- Accumulate NAL bytes in ByteArrayOutputStreams, not boxed ArrayList<Int>
- Delete the dead NSD reflection fallback (ResolutionListener never
  existed; the classic API is present from API 16 through 36)
- Hold decoderLock around all MediaCodec calls (not thread-safe) and make
  requestPli thread-safe
- Update RUNBOOK quirks (NSD, setOutputSurface) and MEMORY notes

docs/RUNBOOK.md

@@ -243,16 +243,20 @@ Platform quirks found while validating (Android 16 / API 36):
 - `DatagramSocket.localPort` gives the bound port; `.port` is -1 for
   unconnected datagram sockets, and `.localAddress` is an `InetAddress`
   (Inet6Address on Android), not an `InetSocketAddress`.
-- `MediaCodec`: pass the output Surface to `configure()` (`setOutputSurface`
-  is illegal after configure); call `start()`; render with
-  `releaseOutputBuffer(index, render=true)`; the C2 AVC decoder requires a
-  concrete width/height at configure (use a placeholder — the in-band SPS
-  reconfigures it).
+- `MediaCodec`: pass the output Surface to `configure()` — the codec must
+  start in surface mode (`setOutputSurface` afterwards only switches an
+  already-surface-mode codec to a new surface; a codec configured without
+  a surface can never take one, per the API docs); call `start()`; render
+  with `releaseOutputBuffer(index, render=true)`; the C2 AVC decoder
+  requires a concrete width/height at configure (use a placeholder — the
+  in-band SPS reconfigures it).
 - `MediaFormat.format()` / `KEY_MIME_TYPE` are not in the API-36 public
   surface.
-- NSD: API 36 replaced `ResolutionListener` registration with
-  `registerService(info, flags, RegistrationListener)`; the app falls back
-  to reflection on older devices.
+- NSD: the classic `registerService(info, flags, RegistrationListener)`
+  API exists from API 16 through 36 (verified with javap on the android-36
+  SDK jar) — no fallback is needed. A reflection fallback targeting a
+  pre-36 "ResolutionListener" was removed: that class never existed at
+  any API level, so the fallback could only ever fail.
 - The C2 decoder scales its output to the Surface (`android._video-scaling`)
   — letterbox by **sizing the TextureView to the video aspect** (centered
   on a black window background), not with a transform matrix (double scale).