Add Chrome extension cookie bridge for session import

Users logged into Alta in Chrome can now send their session cookie
to the running Electron app via a local HTTP server on port 18247,
eliminating the need for re-authentication.

- main.js: HTTP cookie server with CORS, token, domain validation
- preload.js: onExtensionCookie push-pattern IPC bridge
- renderer.js: handleExtensionCookie sets session, fetches devices
- chrome-extension/: Manifest V3 extension with popup UI
- CLAUDE.md: updated architecture docs

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

renderer.js

@@ -996,6 +996,44 @@ async function deleteProfile(profileId) {
 
 // toggleCookieSection is attached via addEventListener in the event listeners section above
 
+// Handle cookie received from Chrome extension via local HTTP bridge
+async function handleExtensionCookie(data) {
+    const { deploymentUrl, cookies, cookieValue } = data;
+
+    // If already connected, disconnect first
+    if (sessionData.isConnected) {
+        handleDisconnect();
+    }
+
+    // Set session state from extension cookie
+    sessionData.deploymentUrl = deploymentUrl;
+    sessionData.cookies = cookies;
+    sessionData.isConnected = true;
+
+    showStatus(connectionStatus, `Connected via Chrome extension to ${deploymentUrl}`, 'success');
+    updateConnectionStatus(true);
+    updateButtonStates();
+
+    // Auto-populate cookie key and expand cookie proxy section
+    cookieKey.value = cookieValue;
+    const cookieContent = document.getElementById('cookieProxyContent');
+    const cookieIcon = document.getElementById('cookieCollapseIcon');
+    if (cookieContent.style.display === 'none') {
+        cookieContent.style.display = 'block';
+        cookieIcon.textContent = '\u25B2';
+        cookieIcon.classList.add('expanded');
+    }
+    updateCookieProxyButtonStates();
+
+    // Fetch devices
+    try {
+        await handleGetDevices();
+    } catch (err) {
+        console.error('Failed to fetch devices after extension cookie:', err);
+        showStatus(deviceStatus, 'Connected, but failed to load devices.', 'warning');
+    }
+}
+
 // Initialize the app
 document.addEventListener('DOMContentLoaded', async () => {
     console.log('Alta Video Camera Proxy loaded');
@@ -1003,10 +1041,13 @@ document.addEventListener('DOMContentLoaded', async () => {
     // Initialize connection status
     updateConnectionStatus(false);
     updateButtonStates();
-    
+
+    // Listen for cookies pushed from Chrome extension
+    window.electronAPI.onExtensionCookie(handleExtensionCookie);
+
     // Load saved profiles
     await loadProfiles();
-    
+
     // Check camera proxy executable availability
     await checkCameraProxyAvailability();
 });