feat(02-02): implement ESP32Transport UDP client with asyncio DatagramProtocol

- ESP32Transport.send_command() injects v:1, fire-and-forget, silent drop if not ready
- 512-byte payload limit enforced with warning log
- datagram_received() parses STATUS ok → connected=True, stores last_status
- on_status callback support for status update notifications
- connection_lost() sets connected=False, clears transport ref
- create_esp32_transport() async factory sends initial STATUS ping (D-12)
- All protocol behaviors match docs/protocol.md exactly (D-10, D-11, D-12, D-14)
- Add pytest-asyncio to dev deps + asyncio_mode=auto for test suite

tests/test_player_smoke.py

@@ -0,0 +1,32 @@
+"""
+Manual smoke test for AudioPlayer — requires an actual audio file.
+Not part of the automated test suite.
+
+Run: uv run python tests/test_player_smoke.py /path/to/test.mp3
+"""
+import sys
+import time
+from led_sync.audio.player import AudioPlayer
+
+
+def main():
+    if len(sys.argv) < 2:
+        print("Usage: uv run python tests/test_player_smoke.py <audio_file>")
+        sys.exit(1)
+
+    p = AudioPlayer()
+    p.play(sys.argv[1])
+    time.sleep(3)
+    print(f"Position: {p.position_seconds:.2f}s")
+    p.pause()
+    print(f"Paused at: {p.position_seconds:.2f}s")
+    time.sleep(1)
+    p.resume()
+    time.sleep(2)
+    print(f"After resume: {p.position_seconds:.2f}s")
+    p.stop()
+    print("Done")
+
+
+if __name__ == "__main__":
+    main()