Improve MCP settings auth flow, remote config support, and diagnostics UX (#953)

* feat: improve MCP settings auth workflow

* fix: complete MCP settings auth flow

* fix: harden MCP settings auth flow

* fix: add MCP settings refresh control

* fix: stabilize MCP authorization and status handling

* fix: clarify MCP advanced remote options toggle

* fix: improve MCP import and diagnostics

* feat: improve MCP settings panel visual hierarchy and UX

* fix: expose MCP auth actions in connected state

* fix: remove MCP import snippet helper text

* fix: address MCP review feedback

* fix: correct MCP page transport layout after rebase

packages/ui/src/App.tsx

@@ -53,6 +53,8 @@ import { useFeatureFlagsStore } from '@/stores/useFeatureFlagsStore';
 import type { RuntimeAPIs } from '@/lib/api/types';
 import { TooltipProvider } from '@/components/ui/tooltip';
 import { QuickOpenDialog } from '@/components/ui/QuickOpenDialog';
+import { McpOAuthCallbackPage } from '@/components/sections/mcp/McpOAuthCallbackPage';
+import { MCP_OAUTH_CALLBACK_PATH } from '@/components/sections/mcp/mcpOAuth';
 
 const AboutDialogWrapper: React.FC = () => {
   const isAboutDialogOpen = useUIStore((s) => s.isAboutDialogOpen);
@@ -105,6 +107,14 @@ const readEmbeddedSessionChatConfig = (): EmbeddedSessionChatConfig | null => {
   };
 };
 
+const isMcpOAuthCallbackPath = (): boolean => {
+  if (typeof window === 'undefined') {
+    return false;
+  }
+
+  return window.location.pathname === MCP_OAUTH_CALLBACK_PATH;
+};
+
 const EmbeddedSessionSelectionGate: React.FC<{
   embeddedSessionChat: EmbeddedSessionChatConfig | null;
   isVSCodeRuntime: boolean;
@@ -192,6 +202,7 @@ function App({ apis }: AppProps) {
   const appReadyDispatchedRef = React.useRef(false);
   const embeddedSessionChat = React.useMemo<EmbeddedSessionChatConfig | null>(() => readEmbeddedSessionChatConfig(), []);
   const embeddedBackgroundWorkEnabled = !embeddedSessionChat || isEmbeddedVisible;
+  const isMcpOAuthCallback = React.useMemo(() => isMcpOAuthCallbackPath(), []);
 
   React.useEffect(() => {
     setStreamPerfEnabled(showMemoryDebug);
@@ -684,6 +695,14 @@ function App({ apis }: AppProps) {
     );
   }
 
+  if (isMcpOAuthCallback) {
+    return (
+      <ErrorBoundary>
+        <McpOAuthCallbackPage />
+      </ErrorBoundary>
+    );
+  }
+
   // VS Code runtime - simplified layout without git/terminal views
   if (isVSCodeRuntime) {
     // Check if this is the Agent Manager panel