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.
Phase 4 - Stream Health and Fallback:
- StreamHealthChecker with partial GET validation of m3u8 content
- Bitrate extraction from BANDWIDTH tags
- Response time measurement for quality ranking
- Fallback ordering: live first, fastest response time first
- GET /streams now only returns health-verified streams
Phase 5 - HLS Proxy Core:
- GET /proxy?url= - m3u8 playlist fetch with full URI rewriting
- GET /relay?url= - chunked segment relay (never buffers full segment)
- m3u8 rewriter handles master, variant, and segment URIs
- Base64url encoding for URL parameters
- CORS middleware for browser playback
- Range header forwarding for seeking support
- 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
