feat(cli): add agent composer UI and refactor text input handling

- Extract shared BaseTextInput component with readline keyboard handling
- Add AgentComposer and AgentFooter components for agent interaction
- Add useAgentStreamingState hook for managing agent streaming state
- Refactor InputPrompt to use BaseTextInput with agent tab bar focus support
- Move calculatePromptWidths to shared layoutUtils
- Disable auto-accept indicator on agent tabs (agents handle their own)

This enables a dedicated input experience for agent tabs with proper
focus management and keyboard navigation between main input and agent tabs.

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

packages/cli/src/ui/AppContainer.tsx

@@ -676,16 +676,17 @@ export const AppContainer = (props: AppContainerProps) => {
   // Track whether suggestions are visible for Tab key handling
   const [hasSuggestionsVisible, setHasSuggestionsVisible] = useState(false);
 
-  // Auto-accept indicator
+  const agentViewState = useAgentViewState();
+
+  // Auto-accept indicator — disabled on agent tabs (agents handle their own)
   const showAutoAcceptIndicator = useAutoAcceptIndicator({
     config,
     addItem: historyManager.addItem,
     onApprovalModeChange: handleApprovalModeChange,
     shouldBlockTab: () => hasSuggestionsVisible,
+    disabled: agentViewState.activeView !== 'main',
   });
 
-  const agentViewState = useAgentViewState();
-
   const { messageQueue, addMessage, clearQueue, getQueuedMessagesText } =
     useMessageQueue({
       isConfigInitialized,