feat: setup project infrastructure

- Create folder structure (server, client, install)
- Add server package.json with LiveKit SDK, Express, Opus
- Add client package.json with React, Vite, livekit-client
- Add macOS installation script with LiveKit binary download
- Add basic YAML config (1 group, 2 channels, audio quality settings)
- Add .gitignore for dependencies and binaries

server/package.json

@@ -0,0 +1,28 @@
+{
+  "name": "ptt-live-server",
+  "version": "0.1.0",
+  "description": "PTT Live - Professional WebRTC Intercom Server",
+  "main": "index.js",
+  "type": "module",
+  "scripts": {
+    "start": "node index.js",
+    "dev": "node --watch index.js",
+    "test": "node --test"
+  },
+  "keywords": ["webrtc", "intercom", "livekit", "audio", "ptt"],
+  "author": "",
+  "license": "MIT",
+  "dependencies": {
+    "express": "^4.19.2",
+    "livekit-server-sdk": "^2.6.0",
+    "yaml": "^2.4.2",
+    "node-opus": "^0.3.3",
+    "ws": "^8.17.0"
+  },
+  "devDependencies": {
+    "nodemon": "^3.1.0"
+  },
+  "engines": {
+    "node": ">=20.0.0"
+  }
+}