Broadcastify Desktop 0.4.75

Broadcastify Desktop 0.4.75 keeps one sequential scheduled downloader active while local transcription and analysis run. The local processing worker is restricted to validated retained source snapshots; account caps, throttling, current-coverage priority, and recent-only account reserves remain enforced.

The Library refreshes its backlog and coverage every ten seconds while open, shows when counts were updated and how many days await analysis, and preserves recording playback during background refresh.

Validation: 348 offline tests, native Release build, nine UI layouts and docking checks, and a real-worker UI regression for backlog refresh during an active pipeline. The public installer passes the package smoke and forbidden-file/secret scans.