* Fix race condition and ensure correct message ordering in
connection establishment
Reorder operations in OpenConn to register the connection before
waiting for peer availability. This ensures:
- Connection is ready to receive messages before peer subscription
completes
- Transport messages and onconnected events maintain proper ordering
- No messages are lost during the connection establishment window
- Concurrent OpenConn calls cannot create duplicate connections
If peer availability check fails, the pre-registered connection is
properly cleaned up.
* Handle service shutdown during relay connection initialization
Ensure relay connections are properly cleaned up when the service is not running by verifying `serviceIsRunning` and removing stale entries from `c.conns` to prevent unintended behaviors.
1. When AddDomain() is called (when proxy receives a new mapping), it now spawns a goroutine to prefetch the certificate
2. prefetchCertificate() creates a synthetic tls.ClientHelloInfo and calls GetCertificate() to trigger the ACME flow
3. The certificate is cached by autocert.DirCache, so subsequent real requests will use the cached cert
4. If the cert is already cached (e.g., proxy restart), GetCertificate just returns it without making ACME requests
- Rewrite Host header to backend target (configurable via pass_host_header per mapping)
- Strip and set X-Forwarded-For/X-Real-IP from direct connection (trust boundary)
- Set X-Forwarded-Host and X-Forwarded-Proto headers
- Strip nb_session cookie and session_token query param before forwarding
- Add --forwarded-proto flag (auto/http/https) for proto detection
- Fix OIDC redirect hardcoded https scheme
- Add pass_host_header to proto, API, and management model
