test: fix pre-existing failures — localStorage polyfill + prefs shape drift

- jsdom 29's localStorage methods are undefined under this vitest config, so
  every frontend test calling localStorage.clear()/setItem() threw. Add a
  shared in-memory Web Storage polyfill via setupFiles (no-op when a working
  Storage exists / in node env). Fixes quick-reply, push, projects-panel (135 tests).
- Update desktop prefs test: defaultPrefs gained remoteHosts/selectedHostId
  (remote-host mTLS work); sync EXPECTED_DEFAULTS and the round-trip fixture.

Full suite now green: 1473 passed (was 142 failing).

test/setup/local-storage.ts

@@ -0,0 +1,66 @@
+/**
+ * test/setup/local-storage.ts — in-memory Web Storage polyfill for the test env.
+ *
+ * jsdom 29 (the `@vitest-environment jsdom` files) exposes a `localStorage`
+ * object whose Storage methods (getItem/setItem/clear/…) are `undefined` under
+ * this vitest config — so any test that calls `localStorage.clear()` throws
+ * "localStorage.clear is not a function". This registered setupFile installs a
+ * spec-compliant in-memory Storage whenever the ambient one is missing or
+ * non-functional, so frontend unit tests (quick-reply, push, projects-panel)
+ * get real persistence semantics. It is a no-op if a working Storage already
+ * exists, and harmless in the node environment (just adds an unused global).
+ */
+
+class MemoryStorage implements Storage {
+  private store = new Map<string, string>()
+
+  get length(): number {
+    return this.store.size
+  }
+
+  clear(): void {
+    this.store.clear()
+  }
+
+  getItem(key: string): string | null {
+    return this.store.has(key) ? (this.store.get(key) as string) : null
+  }
+
+  setItem(key: string, value: string): void {
+    this.store.set(String(key), String(value))
+  }
+
+  removeItem(key: string): void {
+    this.store.delete(key)
+  }
+
+  key(index: number): string | null {
+    return Array.from(this.store.keys())[index] ?? null
+  }
+}
+
+/** True when `s` is a usable Storage (has a callable `clear`). */
+function isUsableStorage(s: unknown): s is Storage {
+  return s != null && typeof (s as Storage).clear === 'function'
+}
+
+/** Install an in-memory Storage on `target[name]` unless a working one exists. */
+function ensureStorage(target: Record<string, unknown>, name: string): void {
+  if (isUsableStorage(target[name])) return
+  Object.defineProperty(target, name, {
+    value: new MemoryStorage(),
+    configurable: true,
+    writable: true,
+  })
+}
+
+const globalTarget = globalThis as unknown as Record<string, unknown>
+ensureStorage(globalTarget, 'localStorage')
+ensureStorage(globalTarget, 'sessionStorage')
+
+// Mirror onto `window` (jsdom env) so `window.localStorage` resolves too.
+const win = (globalThis as { window?: Record<string, unknown> }).window
+if (win) {
+  ensureStorage(win, 'localStorage')
+  ensureStorage(win, 'sessionStorage')
+}