Add server deps and test script to desktop-client package

desktop-client/package.json

@@ -0,0 +1,35 @@
+{
+  "name": "whats-that-music-client",
+  "version": "1.0.0",
+  "description": "Single-app YouTube Music player + now-playing overlay server for OBS",
+  "main": "index.js",
+  "scripts": {
+    "start": "electron .",
+    "test": "node --test 'tests/**/*.test.js'",
+    "build": "electron-builder"
+  },
+  "build": {
+    "appId": "com.whatsthatmusic.client",
+    "productName": "WhatsThatMusic",
+    "files": [
+      "**/*",
+      "!tests/**",
+      "../overlay/**/*"
+    ],
+    "extraMetadata": {
+      "main": "index.js"
+    },
+    "win": {
+      "target": "zip"
+    }
+  },
+  "dependencies": {
+    "electron-store": "^8.1.0",
+    "express": "^5.2.1",
+    "ws": "^8.20.0"
+  },
+  "devDependencies": {
+    "electron": "^33.0.0",
+    "electron-builder": "^25.0.0"
+  }
+}