feat: #1 telemetry record/playback with auto-race detection

- TelemetryRecorder: manual + auto mode (IsRaceOn edge detection)
- TelemetryPlayer: timed packet replay into _handle_packet pipeline
- .tsr format: [uint32 elapsed_ms][uint32 len][bytes]
- Settings UI: start/stop, auto toggle, recording list, play button
- API: /record/*, /playback/*, /recordings

server/api.py

@@ -422,3 +422,50 @@ async def api_update_forward_targets(data: dict[str, Any]):
     save_config(cfg)
     telemetry_listener.forwarder.reload_targets()
     return {"ok": True, "active": telemetry_listener.forwarder.active}
+
+
+# ---- Record & Playback ----
+from server.recorder import TelemetryRecorder, TelemetryPlayer
+
+_recorder = None
+_player = None
+
+def _get_recorder():
+    global _recorder
+    if _recorder is None: _recorder = TelemetryRecorder(telemetry_listener)
+    return _recorder
+
+def _get_player():
+    global _player
+    if _player is None: _player = TelemetryPlayer(telemetry_listener)
+    return _player
+
+@router.post("/record/start")
+async def api_start_record():
+    _get_recorder().start()
+    return {"ok": True, "recording": True}
+
+@router.post("/record/stop")
+async def api_stop_record():
+    _get_recorder().stop()
+    return {"ok": True, "recording": False}
+
+@router.get("/record/status")
+async def api_record_status():
+    return {"recording": _get_recorder().is_recording, "playing": _get_player().is_playing}
+
+@router.get("/recordings")
+async def api_list_recordings():
+    return TelemetryPlayer.list_recordings()
+
+@router.post("/playback/start")
+async def api_start_playback(data: dict):
+    filename = data.get("filename", "")
+    if not filename: raise HTTPException(400, "filename required")
+    _get_player().start(filename)
+    return {"ok": True, "playing": True}
+
+@router.post("/playback/stop")
+async def api_stop_playback():
+    _get_player().stop()
+    return {"ok": True, "playing": False}