Add example to JobUpdate schema and complete OpenAPI compliance

Co-authored-by: nolan1999 <54246789+nolan1999@users.noreply.github.com>

Author: Copilot

api/schemas/job_update.py

@@ -7,3 +7,12 @@ class JobUpdate(BaseModel):
     job_id: int
     status: JobStates
     runtime_details: str | None = None
+
+    class Config:
+        schema_extra = {
+            "example": {
+                "job_id": 12345,
+                "status": "finished",
+                "runtime_details": "Job completed successfully in 45 minutes"
+            }
+        }