Set busy_timeout before journal_mode=WAL in db.ts so SQLite retries
for 10s instead of failing immediately with the default 0ms timeout.
Extract migration into a dedicated Docker Compose service so both
jetstream and api wait for it to complete before opening the database.
Jetstream was running backgrounded in the same container as the API server,
so crashes went undetected and Docker never restarted it. Now each process
runs as a separate docker-compose service with independent restart policies.
Also adds cursor persistence to SQLite (saved every 5s) so restarts resume
from where they left off, moves event destructuring inside try/catch blocks,
and adds global unhandled error/rejection handlers for crash visibility.
