fix(issue): Replace stopwatch toggle with explicit start/stop actions (#34818)

This PR fixes a state de-synchronization bug with the issue stopwatch,
it resolves the issue by replacing the ambiguous `/toggle` endpoint
with two explicit endpoints: `/start` and `/stop`.

- The "Start timer" button now exclusively calls the `/start` endpoint.
- The "Stop timer" button now exclusively calls the `/stop` endpoint.

This ensures the user's intent is clearly communicated to the server,
eliminating the state inconsistency and fixing the bug.

---------

Signed-off-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

templates/swagger/v1_json.tmpl

@@ -11635,7 +11635,7 @@
             "$ref": "#/responses/notFound"
           },
           "409": {
-            "description": "Cannot cancel a non existent stopwatch"
+            "description": "Cannot cancel a non-existent stopwatch"
           }
         }
       }
@@ -11741,7 +11741,7 @@
             "$ref": "#/responses/notFound"
           },
           "409": {
-            "description": "Cannot stop a non existent stopwatch"
+            "description": "Cannot stop a non-existent stopwatch"
           }
         }
       }