feat: add plan mode frontend support with mode toggle and plan review UI

- Add InteractionMode type and ExitPlanModeRequestedEvent to sidecar contracts
- Add PendingPlanReviewRecord domain type and interactionMode to SessionRecord
- Wire onExitPlanMode callback through SidecarClient and RunTurnPendingCommand
- Pass session interaction mode to RunTurnCommand for sidecar consumption
- Handle exit-plan-mode-requested events in AryxAppService
- Add setSessionInteractionMode and dismissSessionPlanReview IPC methods
- Create PlanReviewBanner component with summary, markdown content, and actions
- Add plan mode toggle pill in ChatPane composer area
- Wire implement action as follow-up message (graceful degradation)
- Clear pending plan review on new turn, turn completion, and cancellation

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

src/shared/contracts/channels.ts

@@ -27,6 +27,8 @@ export const ipcChannels = {
   cancelSessionTurn: 'sessions:cancel-turn',
   resolveSessionApproval: 'sessions:resolve-approval',
   resolveSessionUserInput: 'sessions:resolve-user-input',
+  setSessionInteractionMode: 'sessions:set-interaction-mode',
+  dismissSessionPlanReview: 'sessions:dismiss-plan-review',
   querySessions: 'sessions:query',
   updateSessionModelConfig: 'sessions:update-model-config',
   selectProject: 'selection:project',

src/shared/contracts/ipc.ts

@@ -1,5 +1,5 @@
 import type { ApprovalDecision } from '@shared/domain/approval';
-import type { SidecarCapabilities } from '@shared/contracts/sidecar';
+import type { SidecarCapabilities, InteractionMode } from '@shared/contracts/sidecar';
 import type { PatternDefinition, ReasoningEffort } from '@shared/domain/pattern';
 import type { ProjectRecord } from '@shared/domain/project';
 import type { QuerySessionsInput, SessionQueryResult } from '@shared/domain/sessionLibrary';
@@ -107,6 +107,15 @@ export interface UpdateSessionApprovalSettingsInput {
   autoApprovedToolNames?: string[];
 }
 
+export interface SetSessionInteractionModeInput {
+  sessionId: string;
+  mode: InteractionMode;
+}
+
+export interface DismissSessionPlanReviewInput {
+  sessionId: string;
+}
+
 export interface ElectronApi {
   describeSidecarCapabilities(): Promise<SidecarCapabilities>;
   refreshSidecarCapabilities(): Promise<SidecarCapabilities>;
@@ -134,6 +143,8 @@ export interface ElectronApi {
   cancelSessionTurn(input: CancelSessionTurnInput): Promise<void>;
   resolveSessionApproval(input: ResolveSessionApprovalInput): Promise<WorkspaceState>;
   resolveSessionUserInput(input: ResolveSessionUserInputInput): Promise<WorkspaceState>;
+  setSessionInteractionMode(input: SetSessionInteractionModeInput): Promise<WorkspaceState>;
+  dismissSessionPlanReview(input: DismissSessionPlanReviewInput): Promise<WorkspaceState>;
   updateSessionModelConfig(input: UpdateSessionModelConfigInput): Promise<WorkspaceState>;
   querySessions(input: QuerySessionsInput): Promise<SessionQueryResult[]>;
   selectProject(projectId?: string): Promise<WorkspaceState>;

src/shared/contracts/sidecar.ts

@@ -68,12 +68,15 @@ export interface ValidatePatternCommand {
   pattern: PatternDefinition;
 }
 
+export type InteractionMode = 'interactive' | 'plan';
+
 export interface RunTurnCommand {
   type: 'run-turn';
   requestId: string;
   sessionId: string;
   projectPath: string;
   workspaceKind?: 'project' | 'scratchpad';
+  mode?: InteractionMode;
   pattern: PatternDefinition;
   messages: ChatMessageRecord[];
   tooling?: RunTurnToolingConfig;
@@ -241,6 +244,19 @@ export interface UserInputRequestedEvent {
   allowFreeform?: boolean;
 }
 
+export interface ExitPlanModeRequestedEvent {
+  type: 'exit-plan-mode-requested';
+  requestId: string;
+  sessionId: string;
+  exitPlanId: string;
+  agentId?: string;
+  agentName?: string;
+  summary: string;
+  planContent: string;
+  actions?: string[];
+  recommendedAction?: string;
+}
+
 export interface CommandErrorEvent {
   type: 'command-error';
   requestId: string;
@@ -260,5 +276,6 @@ export type SidecarEvent =
   | AgentActivityEvent
   | ApprovalRequestedEvent
   | UserInputRequestedEvent
+  | ExitPlanModeRequestedEvent
   | CommandErrorEvent
   | CommandCompleteEvent;