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/package.json

@@ -0,0 +1,27 @@
+{
+  "name": "@podman/backend",
+  "version": "0.0.0",
+  "private": true,
+  "type": "module",
+  "main": "./dist/index.js",
+  "scripts": {
+    "dev": "tsx watch src/index.ts",
+    "start": "node dist/index.js",
+    "build": "tsc -p tsconfig.json",
+    "typecheck": "tsc -p tsconfig.json --noEmit"
+  },
+  "dependencies": {
+    "@google/genai": "^2.10.0",
+    "@podman/shared": "workspace:*",
+    "cors": "^2.8.6",
+    "dotenv": "^17.4.2",
+    "express": "^5.2.1",
+    "livekit-server-sdk": "^2.15.5",
+    "octokit": "^5.0.5"
+  },
+  "devDependencies": {
+    "@types/cors": "^2.8.19",
+    "@types/express": "^5.0.6",
+    "tsx": "^4.22.4"
+  }
+}