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

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

backend/app/api/import_admin.py

@@ -15,10 +15,17 @@ import_admin_bp = Blueprint("import_admin", __name__, url_prefix="/api/import")
 async def trigger_scan():
     body = await request.get_json(silent=True) or {}
     mode = body.get("mode", "quick")
-    if mode not in ("quick", "deep"):
-        return jsonify({"error": f"mode {mode!r} not supported; use 'quick' or 'deep'"}), 400
+    if mode not in ("quick", "deep", "verify"):
+        return jsonify({"error": f"mode {mode!r} not supported; use 'quick', 'deep', or 'verify'"}), 400
+
+    # 'verify' is a library task — short-circuit the import_root walk
+    # (no ImportBatch, no per-file ImportTasks).
+    if mode == "verify":
+        from ..tasks.maintenance import verify_integrity
+
+        async_result = verify_integrity.delay()
+        return jsonify({"celery_task_id": async_result.id, "mode": mode}), 202
 
-    # Enqueue the scan task in Celery. The task creates the batch itself.
     from ..tasks.scan import scan_directory
 
     async_result = scan_directory.delay(triggered_by="manual", mode=mode)