feat: Add Comfy Agent service for NODE3 image/video generation

- Create comfy-agent service with FastAPI + NATS integration
- ComfyUI client with HTTP/WebSocket support
- REST API: /generate/image, /generate/video, /status, /result
- NATS subjects: agent.invoke.comfy, comfy.request.*
- Async job queue with progress tracking
- Docker compose configuration for NODE3
- Update PROJECT-MASTER-INDEX.md with NODE2/NODE3 docs

Co-Authored-By: Warp <agent@warp.dev>

services/comfy-agent/app/jobs.py

@@ -0,0 +1,25 @@
+# services/comfy-agent/app/jobs.py
+import uuid
+from typing import Dict, Optional
+from .models import JobStatus, GenType
+
+class JobStore:
+    def __init__(self) -> None:
+        self._jobs: Dict[str, JobStatus] = {}
+
+    def create(self, gen_type: GenType) -> JobStatus:
+        job_id = f"job_{uuid.uuid4().hex}"
+        js = JobStatus(job_id=job_id, type=gen_type, status="queued", progress=0.0)
+        self._jobs[job_id] = js
+        return js
+
+    def get(self, job_id: str) -> Optional[JobStatus]:
+        return self._jobs.get(job_id)
+
+    def update(self, job_id: str, **patch) -> JobStatus:
+        js = self._jobs[job_id]
+        updated = js.model_copy(update=patch)
+        self._jobs[job_id] = updated
+        return updated
+
+JOB_STORE = JobStore()