feat: improve OpenAPI/Swagger documentation

[felippemsc]

Summary

Improve OpenAPI/Swagger documentation for better developer experience.

• Add missing tags (publishers, validate, security) for better endpoint organization
• Add server definitions for production and development environments
• Add authentication documentation to API description
• Add Field descriptions and examples to JWK schema
• Add summaries to all endpoints for cleaner Swagger UI
• Improve health endpoint with proper response model

Changes

File	Change
main.py	Tags, servers, auth docs
schemas/jwk.py	Field descriptions
routes/*.py	Summaries for all endpoints
routes/health.py	Proper response model

Test plan

• All unit tests pass (79/79)
• View Swagger UI at /docs and verify organization
• Check server dropdown shows prod/dev URLs
• Verify JWK schema shows field descriptions

[github-actions]

🚀 Release Candidate Deployed!

Version: v0.0.22-rc.40

The RC has been deployed to the dev environment. Check the /health endpoint to verify.