Add run_migrations function to deploy.sh that automatically applies
pending SQL migrations during deployment. Migrations are run after
config installation and before service restart.
Migration runner:
- Sources /etc/silo/silod.env for SILO_DB_PASSWORD
- Reads DB host/port/name/user from production config.yaml
- Waits for database connectivity (5 retries)
- Applies each migration file in order, skipping already-applied ones
- Gracefully degrades if psql is missing or DB password is not set
This fixes the missing migration 009 (auth tables) that caused:
- 'column created_by of relation projects does not exist'
- 'relation api_tokens does not exist'
Also adds auth environment variables to silod.env.example:
- SILO_SESSION_SECRET
- SILO_ADMIN_USERNAME / SILO_ADMIN_PASSWORD
- SILO_OIDC_CLIENT_SECRET, SILO_LDAP_BIND_PASSWORD
