feat: add getPageMarkdown utility using Mozilla Readability

- Consolidate build scripts into single build-client-bundles.ts
- Add @mozilla/readability for Firefox Reader View content extraction
- New getPageMarkdown() utility extracts main page content as plain text
- Supports search and diff-since-last-call like other utilities
- Add test with file snapshot

playwriter/package.json

@@ -7,7 +7,7 @@
   "types": "dist/index.d.ts",
   "repository": "https://github.com/remorses/playwriter",
   "scripts": {
-    "build": "rm -rf dist *.tsbuildinfo && mkdir dist && bun scripts/build-selector-generator.ts && bun scripts/build-bippy.ts && bun scripts/build-a11y-client.ts && tsc && bun scripts/build-resources.ts",
+    "build": "rm -rf dist *.tsbuildinfo && mkdir dist && bun scripts/build-client-bundles.ts && tsc && bun scripts/build-resources.ts",
     "prepublishOnly": "pnpm build",
     "watch": "tsc -w",
     "cli": "vite-node src/cli.ts",
@@ -32,6 +32,7 @@
     "@types/node": "^24.10.1",
     "@types/ws": "^8.18.1",
     "@vitest/ui": "^4.0.8",
+    "@mozilla/readability": "^0.6.0",
     "bippy": "^0.5.27",
     "devtools-protocol": "^0.0.1568893",
     "image-size": "^2.0.2",