fix(cli): serialize subagent confirmation focus to prevent concurrent input conflicts (#2930)

* fix: serialize subagent confirmation focus to prevent concurrent input conflicts

When multiple subagents run in parallel and each triggers a confirmation
prompt, all prompts previously received keyboard focus simultaneously,
causing a single keypress to be dispatched to every active confirmation.

This change introduces a first-come-first-served focus lock mechanism:
- Track subagents with pending confirmations via a type guard
- Use a useRef-based lock so only one confirmation is focused at a time
- Automatically promote focus to the next pending subagent on resolution
- Show a waiting indicator on non-focused confirmations

Fixes #2929

* fix(cli): use dedicated prop for subagent approval waiting state

---------

Co-authored-by: 思晗 <housihan.hsh@alibaba-inc.com>

packages/cli/src/ui/components/messages/ToolMessage.tsx

@@ -173,12 +173,23 @@ const SubagentExecutionRenderer: React.FC<{
   availableHeight?: number;
   childWidth: number;
   config: Config;
-}> = ({ data, availableHeight, childWidth, config }) => (
+  isFocused?: boolean;
+  isWaitingForOtherApproval?: boolean;
+}> = ({
+  data,
+  availableHeight,
+  childWidth,
+  config,
+  isFocused,
+  isWaitingForOtherApproval,
+}) => (
   <AgentExecutionDisplay
     data={data}
     availableHeight={availableHeight}
     childWidth={childWidth}
     config={config}
+    isFocused={isFocused}
+    isWaitingForOtherApproval={isWaitingForOtherApproval}
   />
 );
 
@@ -249,6 +260,10 @@ export interface ToolMessageProps extends IndividualToolCallDisplay {
   embeddedShellFocused?: boolean;
   config?: Config;
   forceShowResult?: boolean;
+  /** Whether this tool's subagent confirmation prompt should respond to keyboard input. */
+  isFocused?: boolean;
+  /** Whether another subagent's approval currently holds the focus lock, blocking this one. */
+  isWaitingForOtherApproval?: boolean;
 }
 
 export const ToolMessage: React.FC<ToolMessageProps> = ({
@@ -265,6 +280,8 @@ export const ToolMessage: React.FC<ToolMessageProps> = ({
   ptyId,
   config,
   forceShowResult,
+  isFocused,
+  isWaitingForOtherApproval,
 }) => {
   const settings = useSettings();
   const isThisShellFocused =
@@ -370,6 +387,8 @@ export const ToolMessage: React.FC<ToolMessageProps> = ({
                 availableHeight={availableHeight}
                 childWidth={innerWidth}
                 config={config}
+                isFocused={isFocused}
+                isWaitingForOtherApproval={isWaitingForOtherApproval}
               />
             )}
             {effectiveDisplayRenderer.type === 'diff' && (