feat: signup return username

auth/openapi-auth.yaml

@@ -59,29 +59,23 @@ paths:
                   type: string
                   format: password
       responses:
+        # This one also sets two cookies: access_token and refresh_token
         "200":
           description: Sign-in result with JWT
-          # headers: 
-          #   Set-Cookie:
-          #     schema: 
-          #       type: array
-          #       items:
-          #         type: string
-          #     explode: true
-          #     style: simple
           content:
             application/json:
               schema:
                 type: object
                 properties:
-                  success:
-                    type: boolean
                   error:
                     type: string
                     nullable: true
                   user_id:
                     type: string
                     nullable: true
+                  user_name:
+                    type: string
+                    nullable: true
         "401":
           description: Access denied due to invalid credentials
           content: