618dafde85
Plan #693 (frontend). Backend landed in 96fffaf.
- sources store: setBackfill(runs) → startBackfill/stopBackfill ({action}).
- SubscriptionsTab: the deep-scan window.prompt for N runs becomes a
Start/Stop toggle keyed on source.backfill_state.
- SourceRow + SourceCard: the 'backfill (N×)' chip becomes a state badge —
Backfilling (chunk N) / Backfilled / Stalled — and the scan button
toggles between Backfill (mdi-magnify-scan) and Stop (mdi-stop).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>