feat(sync): keycloak as source-of-truth with auto catalog sync and token refresh

backend/app/schemas/login.py

@@ -8,8 +8,10 @@ class LoginRequest(BaseModel):
 
 class LoginResponse(BaseModel):
     access_token: str
+    refresh_token: str | None = None
     token_type: str = "Bearer"
     expires_in: int | None = None
+    refresh_expires_in: int | None = None
     scope: str | None = None
 
 
@@ -21,3 +23,7 @@ class OIDCCodeExchangeRequest(BaseModel):
     code: str
     redirect_uri: str
     code_verifier: str | None = None
+
+
+class RefreshTokenRequest(BaseModel):
+    refresh_token: str