feat(console-web): replace TanStack UI with Solid host pages

- move the management frontend under the wasmeld-console crate
- use a persistent Host shell with disposable iframe page documents
- version Host/Page postMessage state and command contracts
- migrate runtime, service, WIT, invocation, and settings workflows
- add Tailwind CSS v4, responsive layouts, and Host-owned dialogs
- emit a dependency-free PWA worker with API cache exclusions
- remove the superseded root TanStack Start application

crates/wasmeld-console/web/src/host/main.tsx

@@ -0,0 +1,13 @@
+import { render } from "solid-js/web";
+import "../styles/app.css";
+import HostApp from "./app";
+
+const root = document.getElementById("app");
+if (!root) throw new Error("missing #app root");
+render(() => <HostApp />, root);
+
+if (import.meta.env.PROD && "serviceWorker" in navigator) {
+  window.addEventListener("load", () => {
+    void navigator.serviceWorker.register("/sw.js");
+  });
+}