feat: add useProcessorSnapshotById hook for snapshot-by-processorId endpoint

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

ui/src/api/queries/executions.ts

@@ -114,3 +114,25 @@ export function useProcessorSnapshot(
     enabled: !!executionId && index !== null,
   });
 }
+
+export function useProcessorSnapshotById(
+  executionId: string | null,
+  processorId: string | null,
+) {
+  return useQuery({
+    queryKey: ['executions', 'snapshot-by-id', executionId, processorId],
+    queryFn: async () => {
+      const { data, error } = await api.GET(
+        '/executions/{executionId}/processors/by-id/{processorId}/snapshot',
+        {
+          params: {
+            path: { executionId: executionId!, processorId: processorId! },
+          },
+        },
+      );
+      if (error) throw new Error('Failed to load snapshot');
+      return data!;
+    },
+    enabled: !!executionId && !!processorId,
+  });
+}