🚀 feat(auth): support new model API paths in authentication and routing

- Updated TokenAuth middleware to handle requests for both `/v1beta/models/` and `/v1/models/`.
- Adjusted distributor middleware to recognize the new model path.
- Enhanced relay mode determination to include the new model path.
- Added route for handling POST requests to `/models/*path`.

These changes ensure compatibility with the new model API structure, improving the overall routing and authentication flow.

relay/constant/relay_mode.go

@@ -80,7 +80,7 @@ func Path2RelayMode(path string) int {
 		relayMode = RelayModeRerank
 	} else if strings.HasPrefix(path, "/v1/realtime") {
 		relayMode = RelayModeRealtime
-	} else if strings.HasPrefix(path, "/v1beta/models") {
+	} else if strings.HasPrefix(path, "/v1beta/models") || strings.HasPrefix(path, "/v1/models") {
 		relayMode = RelayModeGemini
 	}
 	return relayMode