Add disk-fallback to findReadyArchiveSets: when all archive parts
physically exist on disk with non-zero size and none are actively
downloading/validating, consider the archive ready for extraction.
This fixes episodes being skipped when a download item's status
was not updated to "completed" despite the file being fully written.
Also improve debug server: raise log limit to 10000 lines,
add grep filter, add /session endpoint for raw session data.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Starts an HTTP server on port 9868 (configurable via debug_port.txt)
when debug_token.txt exists in the app runtime directory. Provides
/health, /log, /status, and /items endpoints for live monitoring.
Token-based auth required.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
