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/whip.ts

@@ -0,0 +1,62 @@
+// Minimal WHIP (WebRTC-HTTP Ingestion Protocol) publisher for MediaMTX.
+
+export interface WhipSession {
+  pc: RTCPeerConnection;
+  stop: () => Promise<void>;
+}
+
+export async function publishWhip(
+  whipUrl: string,
+  bearer: string,
+  stream: MediaStream,
+): Promise<WhipSession> {
+  const pc = new RTCPeerConnection();
+  for (const track of stream.getTracks()) {
+    pc.addTransceiver(track, { direction: 'sendonly' });
+  }
+
+  const offer = await pc.createOffer();
+  await pc.setLocalDescription(offer);
+  await waitIceComplete(pc);
+
+  const res = await fetch(whipUrl, {
+    method: 'POST',
+    headers: {
+      'content-type': 'application/sdp',
+      authorization: `Bearer ${bearer}`,
+    },
+    body: pc.localDescription!.sdp,
+  });
+  if (!res.ok) {
+    pc.close();
+    throw new Error(`WHIP publish failed: ${res.status} ${await res.text().catch(() => '')}`);
+  }
+  const location = res.headers.get('location');
+  const answer = await res.text();
+  await pc.setRemoteDescription({ type: 'answer', sdp: answer });
+
+  return {
+    pc,
+    stop: async () => {
+      pc.close();
+      for (const track of stream.getTracks()) track.stop();
+      if (location) {
+        const url = new URL(location, whipUrl).toString();
+        await fetch(url, { method: 'DELETE', headers: { authorization: `Bearer ${bearer}` } }).catch(() => {});
+      }
+    },
+  };
+}
+
+function waitIceComplete(pc: RTCPeerConnection): Promise<void> {
+  if (pc.iceGatheringState === 'complete') return Promise.resolve();
+  return new Promise((resolve) => {
+    const timeout = setTimeout(resolve, 2000); // trickle fallback: send what we have
+    pc.addEventListener('icegatheringstatechange', () => {
+      if (pc.iceGatheringState === 'complete') {
+        clearTimeout(timeout);
+        resolve();
+      }
+    });
+  });
+}