Summary

Fixes #7743

This PR implements a configurable TCP proxy timeout for public database proxies, resolving the issue where connections to long-running database queries were dropped by the hardcoded 1-hour Nginx proxy timeout.

Changes

• Backend: Added proxy_timeout column to all standalone and service database tables.
• Logic: Implemented a ProxyTimeout Trait to normalize timeout values (0 maps to 168h, positive integers map to Ns).
• Action: Updated StartDatabaseProxy to inject proxy_timeout directive into Nginx stream configuration.
• UI: Added “Proxy Timeout (seconds)” input field to all 9 database General settings views with validation.
• Docker: Updated docker-compose.test.yml to include test environment.

Testing

Tested on all supported database types (PostgreSQL, MySQL, MariaDB, Redis, MongoDB, Clickhouse, Dragonfly, Keydb, Service Databases).

Checklist

• Code follows style guidelines of this project
• Self-review of code has been completed
• Added documentation (if applicable)
• Added tests (if applicable)

/claim #7743