Refactor job model and optimize job streaming.

Updated the `JobModel` with foreign key relationships and string-based status to enhance database consistency, and improved job event streaming by using `jsonable_encoder` for better serialization. Also, streamlined dependencies by adding `urllib3` to handle HTTP requests.

backend/app/routers/processing.py

@@ -1,6 +1,7 @@
 import json
 import asyncio
 from fastapi import APIRouter, Depends
+from fastapi.encoders import jsonable_encoder
 from sqlalchemy.orm import Session
 from starlette.responses import StreamingResponse
 from app.models import JobStatus, Jobs as JobModel
@@ -11,15 +12,14 @@ router = APIRouter()
 
 async def job_event_generator(db: Session):
     while True:
-        # Fetch jobs with status TODO
         jobs = db.query(JobModel).filter(JobModel.status == JobStatus.TODO).all()
-
         if jobs:
-            # It's recommended to explicitly communicate IDs clearly
-            job_payload = [{"id": job.id, "parameters": job.parameters} for job in jobs]
+            job_payload = jsonable_encoder(jobs)
             yield f"data: {json.dumps(job_payload)}\n\n"
+        await asyncio.sleep(5)
 
-        await asyncio.sleep(5)  # A reasonable heartbeat/refresh
+
+# A reasonable heartbeat/refresh
 
 
 @router.get("/jobs/stream")