feat: add cross-browser extension with AI reading assistant

- Create Pi Reader browser extension for Chrome/Firefox
- Chrome uses Side Panel API, Firefox uses Sidebar Action API
- Supports both browsers with separate manifests and unified codebase
- Built with mini-lit components and Tailwind CSS v4
- Features model selection dialog with Ollama support
- Hot reload development server watches both browser builds
- Add useDefineForClassFields: false to fix LitElement reactivity

packages/browser-extension/package.json

@@ -0,0 +1,32 @@
+{
+  "name": "@mariozechner/pi-reader-extension",
+  "version": "0.5.43",
+  "private": true,
+  "description": "Browser extension that uses @mariozechner/pi-ai to assist with reading web pages",
+  "type": "module",
+  "main": "dist/background.js",
+  "scripts": {
+    "clean": "rm -rf dist-chrome dist-firefox",
+    "build:chrome": "node ./scripts/build.mjs && tailwindcss -i ./src/app.css -o ./dist-chrome/app.css --minify",
+    "build:firefox": "node ./scripts/build.mjs --firefox && tailwindcss -i ./src/app.css -o ./dist-firefox/app.css --minify",
+    "build": "npm run build:chrome && npm run build:firefox",
+    "dev": "concurrently \"node ./scripts/build.mjs --watch\" \"node ./scripts/build.mjs --firefox --watch\" \"tailwindcss -i ./src/app.css -o ./dist-chrome/app.css --watch\" \"tailwindcss -i ./src/app.css -o ./dist-firefox/app.css --watch\" \"node ./scripts/dev-server.mjs\"",
+    "typecheck": "tsc --noEmit",
+    "check": "npm run typecheck"
+  },
+  "dependencies": {
+    "@mariozechner/mini-lit": "^0.1.4",
+    "@mariozechner/pi-ai": "^0.5.43",
+    "lit": "^3.3.1",
+    "lucide": "^0.544.0",
+    "ollama": "^0.6.0"
+  },
+  "devDependencies": {
+    "@tailwindcss/cli": "^4.0.0-beta.14",
+    "@types/chrome": "^0.1.16",
+    "@types/webextension-polyfill": "^0.12.4",
+    "concurrently": "^9.2.1",
+    "esbuild": "^0.25.10",
+    "ws": "^8.18.0"
+  }
+}