feat: NanoClaude Phase 1 — 비동기 job 기반 AI Gateway 코어 구현

POST /chat → job_id ACK, GET /chat/{job_id}/stream → SSE 스트리밍,
EXAONE Ollama adapter, JobManager, StateStream, Worker 구조

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

nanoclaude/services/state_stream.py

@@ -0,0 +1,55 @@
+"""StateStream — per-job SSE event queue."""
+
+from __future__ import annotations
+
+import asyncio
+import json
+import logging
+from collections.abc import AsyncGenerator
+
+logger = logging.getLogger(__name__)
+
+
+class StateStream:
+    """Manages per-job asyncio.Queue for SSE events."""
+
+    def __init__(self) -> None:
+        self._queues: dict[str, asyncio.Queue] = {}
+
+    def create(self, job_id: str) -> None:
+        self._queues[job_id] = asyncio.Queue()
+
+    async def push(self, job_id: str, event: str, data: dict) -> None:
+        q = self._queues.get(job_id)
+        if q:
+            await q.put((event, data))
+
+    async def push_done(self, job_id: str) -> None:
+        """Push sentinel to signal stream end."""
+        q = self._queues.get(job_id)
+        if q:
+            await q.put(None)
+
+    async def subscribe(self, job_id: str) -> AsyncGenerator[str, None]:
+        """Yield SSE-formatted strings until done sentinel."""
+        q = self._queues.get(job_id)
+        if not q:
+            yield _sse("error", {"message": "Job not found"})
+            return
+
+        while True:
+            item = await q.get()
+            if item is None:
+                break
+            event, data = item
+            yield _sse(event, data)
+
+    def cleanup(self, job_id: str) -> None:
+        self._queues.pop(job_id, None)
+
+
+def _sse(event: str, data: dict) -> str:
+    return f"event: {event}\ndata: {json.dumps(data, ensure_ascii=False)}\n\n"
+
+
+state_stream = StateStream()