Add three new extractors (Streamed.pk, DaddyLive, Aceztrims) for live
F1 streams. Extend ExtractedStream model with stream_type/embed_url
fields, skip health checks for embed streams, fix broken Akamai demo
stream, add variant playlist validation, and add iframe player support
in the frontend for embed-type streams.
- BaseExtractor ABC with health_check method
- ExtractorRegistry with concurrent fan-out extraction
- ExtractionService with in-memory cache and background polling
- DemoExtractor with 3 public HLS test streams
- Adaptive polling: 5min during live sessions, 30min otherwise
- GET /streams, GET /extractors, POST /extract endpoints
