docs: prepare EventForge for public release

[cezikmertcan]

Summary

• add the English service landing page at /
• expose /api/meta for machine-readable service metadata
• add full README, architecture, deployment, contribution, and security guides
• generate XML documentation for Swagger
• remove production localhost MongoDB/Redis fallbacks
• keep optional admin bootstrap blank by default

Verification

• previous hardening test suite passed 5 tests with coverage
• production launch fails fast when required configuration is missing
• release Docker image builds as non-root user 1654 on port 8080
• Docker Compose configuration renders successfully

This is the last private-repository PR before the public-release approval checkpoint.