fix(extension): handle browser error pages gracefully

- Treat chrome error page script failures as transient during injection retries.
- Return safe fallback values for read-only DOM commands when tabs land on browser error pages.
- Improve URL watch handling by checking pending URLs and reporting last seen URL/status on timeout.
- Bump package and extension version to 0.9.6 and add regression coverage for error-page behavior.

extension/manifest.json

@@ -1,7 +1,7 @@
 {
   "manifest_version": 3,
   "name": "browser-cli",
-  "version": "0.9.5",
+  "version": "0.9.6",
   "description": "Control your browser from the terminal via browser-cli",
   "permissions": [
     "tabs",