fix: SQLite WAL/busy timeout and allow migrate on failed runs

feat: taxonomy catch-alls, scan/migrate fixes, and tag recall/FP benchmarks

feat: robust GIF/video presence classification pipeline

feat: hybrid real-life filter, review/migrate fixes, and faster media runs

Implement destination folder validation in migrate_run function. Add checks to ensure the destination folder exists and is a directory, with appropriate error handling and logging for failed migrations. This enhances the robustness of the migration process by preventing invalid paths from causing issues.