Summary\n- convert to stream SQL dump output in batches (reduced peak memory pressure)\n- add async dump job flow for large exports:\n - to start job\n - for status/progress\n - for artifact download once completed\n- persist dump job/chunk state in internal SQLite temp tables for resumable progress\n- add/adjust tests for streaming and async dump jobs\n\n## Why\nFixes large-database dump reliability by avoiding single in-memory dump generation and providing a non-blocking job-based path for long-running exports.\n\n## Test\n- \n\n/claim #59