feat(backend): scaffold PodMan agent pipeline + token server

Express server with /health and a LiveKit token endpoint. Module skeletons
for the full loop: vision (Gemini), GitHub fusion, collision detector (pure,
testable), intervention engine, and continual-learning memory store. Approve
native build scripts (esbuild/genai/protobufjs) at the workspace root.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/src/livekit/token.ts

@@ -0,0 +1,25 @@
+import { AccessToken } from 'livekit-server-sdk';
+import { env } from '../env.js';
+
+/**
+ * Mint a LiveKit access token so an engineer's browser can join a pod room
+ * and publish screen + mic + cam tracks.
+ */
+export async function createPodToken(
+  podId: string,
+  identity: string,
+  name?: string,
+): Promise<string> {
+  const at = new AccessToken(env.livekit.apiKey, env.livekit.apiSecret, {
+    identity,
+    name,
+  });
+  at.addGrant({
+    room: podId,
+    roomJoin: true,
+    canPublish: true,
+    canSubscribe: true,
+    canPublishData: true,
+  });
+  return at.toJwt();
+}