feat: add MCP OAuth authentication frontend wiring and banner

- Add McpOauthRequiredEvent and McpOauthStaticClientConfigEvent to sidecar contracts
- Add PendingMcpAuthRecord domain type with status tracking (pending/authenticating/failed/done)
- Add pendingMcpAuth field to SessionRecord for session-level auth state
- Wire onMcpOAuthRequired callback through sidecarProcess, runTurnPending, and AryxAppService
- Handle mcp-oauth-required events: set session pendingMcpAuth, clear on turn finalize/cancel
- Add dismissSessionMcpAuth IPC channel with preload binding and handler registration
- Create McpAuthBanner component (amber-themed, shows server name/URL, dismiss button)
- Integrate McpAuthBanner into ChatPane with placeholder text and App.tsx callback
- Update test fixtures for new RunTurnPendingCommand.onMcpOAuthRequired field

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/shared/contracts/channels.ts

@@ -29,6 +29,7 @@ export const ipcChannels = {
   resolveSessionUserInput: 'sessions:resolve-user-input',
   setSessionInteractionMode: 'sessions:set-interaction-mode',
   dismissSessionPlanReview: 'sessions:dismiss-plan-review',
+  dismissSessionMcpAuth: 'sessions:dismiss-mcp-auth',
   querySessions: 'sessions:query',
   updateSessionModelConfig: 'sessions:update-model-config',
   selectProject: 'selection:project',

src/shared/contracts/ipc.ts

@@ -116,6 +116,10 @@ export interface DismissSessionPlanReviewInput {
   sessionId: string;
 }
 
+export interface DismissSessionMcpAuthInput {
+  sessionId: string;
+}
+
 export interface ElectronApi {
   describeSidecarCapabilities(): Promise<SidecarCapabilities>;
   refreshSidecarCapabilities(): Promise<SidecarCapabilities>;
@@ -145,6 +149,7 @@ export interface ElectronApi {
   resolveSessionUserInput(input: ResolveSessionUserInputInput): Promise<WorkspaceState>;
   setSessionInteractionMode(input: SetSessionInteractionModeInput): Promise<WorkspaceState>;
   dismissSessionPlanReview(input: DismissSessionPlanReviewInput): Promise<WorkspaceState>;
+  dismissSessionMcpAuth(input: DismissSessionMcpAuthInput): Promise<WorkspaceState>;
   updateSessionModelConfig(input: UpdateSessionModelConfigInput): Promise<WorkspaceState>;
   querySessions(input: QuerySessionsInput): Promise<SessionQueryResult[]>;
   selectProject(projectId?: string): Promise<WorkspaceState>;

src/shared/contracts/sidecar.ts

@@ -244,6 +244,23 @@ export interface UserInputRequestedEvent {
   allowFreeform?: boolean;
 }
 
+export interface McpOauthStaticClientConfigEvent {
+  clientId: string;
+  publicClient?: boolean;
+}
+
+export interface McpOauthRequiredEvent {
+  type: 'mcp-oauth-required';
+  requestId: string;
+  sessionId: string;
+  oauthRequestId: string;
+  agentId?: string;
+  agentName?: string;
+  serverName: string;
+  serverUrl: string;
+  staticClientConfig?: McpOauthStaticClientConfigEvent;
+}
+
 export interface ExitPlanModeRequestedEvent {
   type: 'exit-plan-mode-requested';
   requestId: string;
@@ -276,6 +293,7 @@ export type SidecarEvent =
   | AgentActivityEvent
   | ApprovalRequestedEvent
   | UserInputRequestedEvent
+  | McpOauthRequiredEvent
   | ExitPlanModeRequestedEvent
   | CommandErrorEvent
   | CommandCompleteEvent;