chore: remove ServiceLink integration

- Drop the ServiceLink submodule, link-serve command, and serve --rpc mode.
- Remove the now-unused httpx dependency and regenerate uv.lock.
- Add a privacy policy for Chrome Web Store publication.
- Refresh extension icons and bump package/extension version to 0.14.2.
- Keep the native TCP serve path as the only remote-control endpoint.

extension/manifest.json

@@ -1,7 +1,7 @@
 {
   "manifest_version": 3,
   "name": "browser-cli",
-  "version": "0.14.1",
+  "version": "0.14.2",
   "description": "Control your browser from the terminal or Python SDK",
   "permissions": [
     "tabs",