feat(frontend): Vue 3 wizard UI (nostr login, episode upload, go-live)

- NIP-07 login → NIP-98 signed request → session cookie
- episode wizard: pick/create podcast (incl. lightning address question),
  browser-side sha256 + BUD-02 blossom upload with progress, feed result page
- live wizard + stream dashboard: OBS server/key (shown once, rotatable),
  browser WHIP publishing (camera or screen), hls.js live preview,
  publish-recording-as-episode flow
- settings view: external blossom URL, relay list, public URL (admin only)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend/src/lib/api.ts

@@ -0,0 +1,37 @@
+// Thin fetch wrapper for the podpuddle API (session cookie auth).
+
+export class ApiError extends Error {
+  constructor(public status: number, message: string) {
+    super(message);
+  }
+}
+
+async function request<T>(method: string, path: string, body?: unknown, headers?: Record<string, string>): Promise<T> {
+  const res = await fetch(path, {
+    method,
+    credentials: 'same-origin',
+    headers: {
+      ...(body !== undefined ? { 'content-type': 'application/json' } : {}),
+      ...headers,
+    },
+    body: body !== undefined ? JSON.stringify(body) : undefined,
+  });
+  if (!res.ok) {
+    let message = res.statusText;
+    try {
+      message = ((await res.json()) as { error?: string }).error ?? message;
+    } catch {
+      /* keep statusText */
+    }
+    throw new ApiError(res.status, message);
+  }
+  return (await res.json()) as T;
+}
+
+export const api = {
+  get: <T>(path: string) => request<T>('GET', path),
+  post: <T>(path: string, body?: unknown, headers?: Record<string, string>) =>
+    request<T>('POST', path, body, headers),
+  put: <T>(path: string, body?: unknown) => request<T>('PUT', path, body),
+  delete: <T>(path: string) => request<T>('DELETE', path),
+};