feat: add ask_user interactive user input to frontend

Wire the sidecar user-input-requested protocol event through the main
process, IPC layer, and renderer UI so agents can ask the user
interactive questions with choices and freeform input.

- Add UserInputRequestedEvent and ResolveUserInputCommand to sidecar
  protocol types
- Add resolveUserInput method to SidecarClient and onUserInput callback
  to runTurn
- Create PendingUserInputRecord domain type and add pendingUserInput to
  SessionRecord
- Add handleUserInputRequested and resolveSessionUserInput to
  AryxAppService with handle management
- Register sessions:resolve-user-input IPC channel with preload bridge
- Create UserInputBanner component with choice buttons and freeform
  input
- Integrate UserInputBanner into ChatPane with header indicator

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

src/shared/contracts/ipc.ts

@@ -36,6 +36,13 @@ export interface ResolveSessionApprovalInput {
   decision: ApprovalDecision;
 }
 
+export interface ResolveSessionUserInputInput {
+  sessionId: string;
+  userInputId: string;
+  answer: string;
+  wasFreeform: boolean;
+}
+
 export interface UpdateSessionModelConfigInput {
   sessionId: string;
   model: string;
@@ -126,6 +133,7 @@ export interface ElectronApi {
   sendSessionMessage(input: SendSessionMessageInput): Promise<void>;
   cancelSessionTurn(input: CancelSessionTurnInput): Promise<void>;
   resolveSessionApproval(input: ResolveSessionApprovalInput): Promise<WorkspaceState>;
+  resolveSessionUserInput(input: ResolveSessionUserInputInput): Promise<WorkspaceState>;
   updateSessionModelConfig(input: UpdateSessionModelConfigInput): Promise<WorkspaceState>;
   querySessions(input: QuerySessionsInput): Promise<SessionQueryResult[]>;
   selectProject(projectId?: string): Promise<WorkspaceState>;