feat(m2): live video to stock Moonlight — ENet control + video data plane

A stock Moonlight client now decodes H.265 from the lumen host end-to-end
(verified at 5120×1440@120 on RTX 5070 Ti):
- control.rs: ENet control host on UDP 47999 (rusty_enet). Moonlight starts the
  control stream before video (STAGE_CONTROL_STREAM_START precedes _VIDEO_), so it
  must be up first — this was the blocker behind the earlier "error 35".
- stream.rs: video data plane — on RTSP PLAY, learn the client endpoint from its
  ping, NVENC-encode at the negotiated mode, packetize (GameStream RTP/NV/FEC),
  send over UDP 47998; stops when the client disconnects.
- rtsp.rs: ANNOUNCE → StreamConfig (resolution/fps/packetSize/bitrate/codec), PLAY
  starts the stream, TEARDOWN stops it; PairStatus=1 over the mutual-TLS port.

P1.3 uses a synthetic test pattern + data-shards-only FEC (clean-LAN). Next: real
portal desktop capture, input injection (decode control → uinput), nanors-exact FEC,
encryption, audio.

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

Cargo.lock

@@ -1458,6 +1458,7 @@ dependencies = [
  "rsa",
  "rustls",
  "rustls-pemfile",
+ "rusty_enet",
  "sha2",
  "tokio",
  "tracing",
@@ -2318,6 +2319,15 @@ dependencies = [
  "wait-timeout",
 ]
 
+[[package]]
+name = "rusty_enet"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e1c0b43e27d8d86bb3a15b9eac232b6d78a06afee258a9861deb5a0d15b65c33"
+dependencies = [
+ "js-sys",
+]
+
 [[package]]
 name = "ryu"
 version = "1.0.23"