initial version, can start a server that serves the diff, gen an html file in tmp and open it or generate it in a specific location

package.json

@@ -0,0 +1,18 @@
+{
+  "name": "difftool",
+  "version": "0.1.0",
+  "type": "module",
+  "private": true,
+  "dependencies": {
+    "@pierre/diffs": "^1.2.7",
+    "@pierre/trees": "^1.0.0-beta.4",
+    "express": "^5.1.0"
+  },
+  "scripts": {
+    "build": "esbuild src/client.js --bundle --outfile=public/client.js --format=esm",
+    "postinstall": "npm run build"
+  },
+  "devDependencies": {
+    "esbuild": "^0.28.0"
+  }
+}