Caster 0.5.5 — Cast connection stability

Fixes HLS restart continuity errors that can disconnect Chromecast receivers such as RB Room. Preserves segment numbering across source restarts, removes duplicate restart markers, and preserves timeline IDs as playlists advance. Also normalizes Windows WAV detection. Validation: 286 offline tests passed, five consecutive real ffmpeg runs preserved segment and timeline identities, and the portable archive passed integrity checks. Physical TV playback has not yet been verified.