fix(extension): detect browser error pages earlier

- Add shared browser error URL detection for Chrome, Edge, Brave, and Firefox-style about:error pages.
- Short-circuit read-only DOM and HTML commands with safe fallbacks when tabs are already on browser error pages.
- Fail navigation waits, DOM waits, polling, and URL watches with clearer error-page messages.
- Bump package and extension version to 0.9.8 and extend regression coverage for cross-browser error-page handling.

extension/src/commands/navigation.ts

@@ -1,5 +1,5 @@
 // @ts-nocheck
-import { getActiveTab, getAliases, resolveGroupId, tabInfo } from '../core';
+import { getActiveTab, getAliases, isBrowserErrorUrl, resolveGroupId, tabInfo } from '../core';
 export async function navOpen({ url, background, window: windowName, windowId: explicitWindowId, group: groupNameOrId }) {
   let windowId;
   if (explicitWindowId != null) {
@@ -77,6 +77,10 @@ export async function navWait({ tabId, timeout = 30000, readyState = "complete"
   const interval = 200;
   while (Date.now() < deadline) {
     const t = await chrome.tabs.get(tab.id);
+    const currentUrl = t.url || t.pendingUrl || "";
+    if (isBrowserErrorUrl(currentUrl)) {
+      throw new Error(`Tab ${tab.id} is showing an error page while waiting for load (${currentUrl})`);
+    }
     if (readyState === "complete" ? t.status === "complete" : t.status !== "loading") {
       return tabInfo(t);
     }