[Enhancement]: Role-Based OpenAPI Documentation Visibility

[tomvothecoder]

Is your feature request related to a problem?

Admin-only endpoints (e.g., /users, /tokens) currently appear in the default OpenAPI schema and Swagger UI for all authenticated users. While route-level authorization prevents access, exposing these endpoints in public docs creates unnecessary visibility and potential confusion.

Describe the solution you'd like

• Tag admin-only endpoints (e.g., tags=["admin"])
• Disable default docs_url and openapi_url
• Implement custom /openapi.json generation
• Filter out admin-tagged endpoints (e.g., /users, /tokens) for non-admin users
• Serve /docs behind authentication
• Maintain route-level authorization enforcement

Describe alternatives you've considered

• Using include_in_schema=False (too static; hides endpoints for admins as well)
• Maintaining separate admin documentation service (adds complexity)

Additional context

This change affects documentation visibility only and does not modify endpoint authorization behavior.