fix: comprehensive extension context invalidated handling

entrypoints/content.ts

@@ -204,7 +204,7 @@ export default defineContentScript({
 
     function isExtensionValid(): boolean {
       try {
-        return !!chrome.runtime?.id;
+        return typeof chrome !== 'undefined' && !!chrome.runtime?.id;
       } catch {
         return false;
       }
@@ -223,6 +223,25 @@ export default defineContentScript({
       setTimeout(() => toast.remove(), 4000);
     }
 
+    // ─── Safe chrome.runtime.sendMessage wrapper ──────────────────────────────
+
+    async function safeSendMessage(payload: Record<string, unknown>): Promise<unknown> {
+      if (!isExtensionValid()) {
+        showErrorToast('LexAI was updated — please refresh this page.');
+        return null;
+      }
+      try {
+        return await chrome.runtime.sendMessage(payload);
+      } catch (err) {
+        if (String(err).includes('Extension context invalidated') ||
+            String(err).includes('message channel closed')) {
+          showErrorToast('LexAI was updated — please refresh this page.');
+          hideToolbar();
+        }
+        return null;
+      }
+    }
+
     // ─── LLM call ─────────────────────────────────────────────────────────────
 
     async function runAction(action: string) {
@@ -251,13 +270,15 @@ export default defineContentScript({
       }
 
       try {
-        const response = await chrome.runtime.sendMessage({
+        const response = await safeSendMessage({
           type:    'ANALYZE_TEXT',
           payload: { text: textToProcess, action },
-        });
+        }) as { error?: string; result?: string } | null;
 
         hideToolbar();
 
+        if (response === null) return; // safeSendMessage already handled the error
+
         if (response?.error) {
           showModal(`❌ ${response.error}`, null);
         } else {
@@ -265,8 +286,9 @@ export default defineContentScript({
         }
       } catch (err) {
         hideToolbar();
-        if (String(err).includes('Extension context invalidated')) {
-          showErrorToast('LexAI was updated. Please refresh the page.');
+        if (String(err).includes('Extension context invalidated') ||
+            String(err).includes('message channel closed')) {
+          showErrorToast('LexAI was updated — please refresh this page.');
         } else {
           showModal(`❌ Error: ${String(err)}`, null);
         }
@@ -440,6 +462,25 @@ export default defineContentScript({
       document.body.appendChild(modal);
     }
 
+    // ─── Global extension context error handlers ──────────────────────────────
+
+    window.addEventListener('error', (e) => {
+      if (e.message?.includes('Extension context invalidated')) {
+        e.preventDefault(); // suppress console error
+        hideToolbar();
+        showErrorToast('LexAI was updated — please refresh this page.');
+      }
+    });
+
+    window.addEventListener('unhandledrejection', (e) => {
+      if (String(e.reason)?.includes('Extension context invalidated') ||
+          String(e.reason)?.includes('message channel closed')) {
+        e.preventDefault();
+        hideToolbar();
+        showErrorToast('LexAI was updated — please refresh this page.');
+      }
+    });
+
     // ─── Event listeners ──────────────────────────────────────────────────────
 
     document.addEventListener('mouseup', (e) => {