feat(integrity): /trigger accepts mode=verify → enqueues verify_integrity

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/test_api_import_admin.py

@@ -114,3 +114,26 @@ async def test_trigger_accepts_deep(client, monkeypatch):
 async def test_trigger_still_rejects_unknown_mode(client):
     resp = await client.post("/api/import/trigger", json={"mode": "wat"})
     assert resp.status_code == 400
+
+
+@pytest.mark.asyncio
+async def test_trigger_accepts_verify(client, monkeypatch):
+    # Stub the verify task's dispatch so the API contract is asserted
+    # without running the real (eager) verify_integrity end-to-end.
+    from backend.app.tasks import maintenance as m
+
+    seen = {}
+
+    class _Res:
+        id = "celery-verify"
+
+    def _fake_delay():
+        seen["called"] = True
+        return _Res()
+
+    monkeypatch.setattr(m.verify_integrity, "delay", _fake_delay)
+    resp = await client.post("/api/import/trigger", json={"mode": "verify"})
+    assert resp.status_code == 202
+    body = await resp.get_json()
+    assert body["mode"] == "verify"
+    assert seen == {"called": True}