Major production release with SSE fixes and PostgreSQL array support.

SSE Fixes:
- Explicit WriteHeader for immediate header commit
- X-Accel-Buffering for proxy compatibility
- CORS headers for cross-origin requests
- Immediate ping to prevent client timeout

PostgreSQL:
- Fixed array scanning with pgtype.Array[string]
- Helper functions for array conversion

Documentation:
- Complete README with installation/testing
- Environment variable reference
- curl test examples