Separate protocol version from database compatibility version in WebDAV
sync paths. Upload writes to v2/db-v6/<profile>, download falls back to
legacy v2/<profile> when current path has no data. Extend manifest with
optional dbCompatVersion field and add legacy layout detection to UI.
- Add usage_daily_rollups table (schema v6) to aggregate proxy request
logs into daily summaries, reducing query overhead for statistics
- Add rollup_and_prune DAO that aggregates old detail logs (>N days)
into rollup rows and deletes the originals
- Update all usage stats queries to UNION detail logs with rollup data
- Introduce incremental auto-vacuum for SQLite, with startup and
periodic cleanup of old stream_check_logs and request log rollups
- Split backup export/import into full vs sync variants: WebDAV sync
now skips local-only table data (proxy_request_logs,
stream_check_logs, provider_health, proxy_live_backup,
usage_daily_rollups) while preserving them on import
- Add enable_logging guard to skip request log writes when disabled
- Apply cargo fmt formatting fixes across multiple modules
Jason