feat: embedded flow-watcher in API lifespan with startup sync

backend/tests/test_sync.py

@@ -1,7 +1,9 @@
 """Sync engine tests: backend/flows/*.json -> DB + LFX (LFX real, DB sqlite)."""
 
+import asyncio
 import json
 import shutil
+import time
 from pathlib import Path
 from uuid import UUID
 
@@ -9,6 +11,7 @@ import pytest
 
 from app.flows import store, sync
 from app.flows.lfx_client import LfxClient, LfxNotFound
+from app.flows.schemas import SyncReport
 from app.flows.sync import lfx_id_for
 from app.settings import settings
 
@@ -127,3 +130,28 @@ async def test_sync_endpoint_returns_report(client, lfx_server, tmp_path, monkey
 
     response = await client.post("/api/flows/sync")
     assert response.json()["skipped"] == ["simple_rule"]
+
+
+async def test_watch_forever_triggers_on_file_change(tmp_path):
+    import contextlib
+
+    calls: list[str] = []
+    stop = asyncio.Event()
+
+    def run():
+        calls.append("sync")
+        return SyncReport()
+
+    task = asyncio.create_task(sync.watch_forever(stop, tmp_path, run_sync=run))
+    try:
+        await asyncio.sleep(0.5)  # let the watcher arm
+        (tmp_path / "neu.json").write_text("{}")
+        deadline = time.time() + 15
+        while not calls and time.time() < deadline:
+            await asyncio.sleep(0.1)
+        assert calls == ["sync"]
+    finally:
+        stop.set()
+        task.cancel()
+        with contextlib.suppress(asyncio.CancelledError):
+            await task