Implement AXIS parity UI and execution baseline

web/app/browser-opfs-worker.mjs

@@ -0,0 +1,10 @@
+import { runOpfsProbe } from "../workspace/opfs-runtime.mjs";
+
+self.onmessage = async (event) => {
+  try {
+    const result = await runOpfsProbe({ storage: self.navigator?.storage, projectId: event.data?.project_id ?? "s6-05-opfs", mode: event.data?.mode ?? "round_trip", cleanup: event.data?.cleanup !== false });
+    self.postMessage(result);
+  } catch (error) {
+    self.postMessage({ schema: "opfs-runtime.v1", status: "blocked", code: "opfs_worker_exception", reason: error?.name ?? "unknown" });
+  }
+};