fix(live): unblock iPhone first frames and speed up startup

[christopherklint97]

Summary

• Start native iPhone live HLS when its first frame is loaded instead of waiting for paused canplay.
• Limit player guide requests to its scroll viewport, cancel obsolete catalog/guide work, and bound batch concurrency.
• Show elapsed playback loading time and early Retry, plus bounded, actionable app-bootstrap connection states.
• Exclude native compatibility media from service-worker API caching.
• Prewarm and reuse real, catalog-generation-bound directory counts while refreshing them off the startup critical path.

Verification

• Locked frontend dependencies: 426 tests passed; lint, typecheck and production build passed.
• New directory-status cache and channel worker: 10 tests passed; server typecheck passed.
• Full local server suite: 465 passed, 13 skipped; existing FFmpeg timing/fixture cases fail intermittently under Pi disk/CPU contention. Do not treat this as a green full-server gate; packaged CI must run.
• Real deployed cold compatible-HLS probe: authorization 4.256s, playlist 200, MPEG-TS segment 200.
• Measured old app bootstrap status at 40.56s (worker read 42.486s).

Deployment pending verified image and review. User approved a brief archive/playback gap for the restart. Physical iPhone acceptance is not yet verified.