auto-claude: subtask-4-2 - Create gRPC-based delivery routes provider

Add grpcDeliveryRoutesProvider to providers.dart that uses GrpcCqrsApiClient
for fetching delivery routes. Follows the same pattern as the HTTP-based
deliveryRoutesProvider: checks authentication, uses grpcClientProvider,
and handles Result<T> responses with proper error logging.

Co-Authored-By: Claude <noreply@anthropic.com>

.auto-claude-status

@@ -3,23 +3,23 @@
   "spec": "002-migrate-api-routes-from-http-to-grpc",
   "state": "building",
   "subtasks": {
-    "completed": 6,
+    "completed": 9,
     "total": 13,
     "in_progress": 1,
     "failed": 0
   },
   "phase": {
-    "current": "gRPC Client Implementation",
+    "current": "Provider Integration",
     "id": null,
-    "total": 4
+    "total": 3
   },
   "workers": {
     "active": 0,
     "max": 1
   },
   "session": {
-    "number": 7,
+    "number": 10,
     "started_at": "2026-01-20T12:45:59.858836"
   },
-  "last_update": "2026-01-20T13:03:21.219002"
+  "last_update": "2026-01-20T13:08:01.853317"
 }