feat(cli): Add state management and plumbing for agent configuration dialog (#17259)

packages/cli/src/ui/contexts/UIStateContext.tsx

@@ -24,6 +24,7 @@ import type {
   IdeInfo,
   FallbackIntent,
   ValidationIntent,
+  AgentDefinition,
 } from '@google/gemini-cli-core';
 import type { DOMElement } from 'ink';
 import type { SessionStatsState } from '../contexts/SessionContext.js';
@@ -70,6 +71,10 @@ export interface UIState {
   isSettingsDialogOpen: boolean;
   isSessionBrowserOpen: boolean;
   isModelDialogOpen: boolean;
+  isAgentConfigDialogOpen: boolean;
+  selectedAgentName?: string;
+  selectedAgentDisplayName?: string;
+  selectedAgentDefinition?: AgentDefinition;
   isPermissionsDialogOpen: boolean;
   permissionsDialogProps: { targetDirectory?: string } | null;
   slashCommands: readonly SlashCommand[] | undefined;