## Summary
Fixes a concurrent map access vulnerability in the OIDC handler that
could cause remote unauthenticated DoS.
## Changes
- Removed OIDC authorization flow endpoints ( and )
- Removed the unsynchronized map that caused the data race
- Kept only the OIDC token exchange endpoint ()
- Simplified by removing OAuth2 flow dependencies
The map was being accessed concurrently by the start (write) and
callback (read/delete) endpoints without synchronization, causing
runtime panics. Since the token exchange flow doesn't require session
state, removing the authorization flow eliminates the vulnerability
entirely.
## Summary
This PR implements OIDC authentication support for admin users,
specifically configured for Google Cloud Identity. The implementation
includes:
- Configurable OIDC authentication endpoints and validation
- Google Cloud Identity integration for admin access
- JWT token validation and user session management
- Deployment configuration updates for OIDC provider settings
Fixes#283
