StreamQA HLS Health Probe

Live-stream health verdict for any HLS (m3u8) playlist URL. Runs three probe cycles: availability, manifest latency, live-window movement, frozen-playlist detection, segment throughput, rebuffer-risk. Input JSON: {query: https://.../live.m3u8} via the proxy path /run. Output: verdict healthy/degraded/frozen/unreachable plus metrics. For LIVE playlists; VOD reports frozen by design.