Task Log - Fix Docker Healthcheck and Port Conflicts

Actions

Docker Configuration:
- Updated starter/docker-compose.yml postgres healthcheck to explicitly specify the database name (-d ${POSTGRES_DATABASE:-lightrag_multitenant}). This fixes the FATAL: database "lightrag" does not exist errors in the logs.
Test Script:
- Updated starter/test_multi_tenant.sh to check for and kill any process holding port 9621 before starting containers. This resolves the Bind for 0.0.0.0:9621 failed error.

Aggressive Port Cleanup: Added lsof ... | xargs kill -9 to the test script. This is necessary for a reliable "reset and run" experience in a dev environment where zombie processes might linger.
Healthcheck Precision: The default pg_isready behavior (using username as dbname) was incorrect for our setup where POSTGRES_USER=lightrag but POSTGRES_DB=lightrag_multitenant. Explicitly setting the database fixes the false negative healthchecks.

Run the Test Script:
```
cd starter
./test_multi_tenant.sh
```
Verify Fixes:
- Watch the logs (via docker-compose logs -f if needed) to ensure no more "database does not exist" errors appear.
- Confirm the API container starts successfully without port conflict errors.
- Proceed with WebUI verification at http://localhost:3000.