feat(core,cli)!: Implement in-process agent backend for arenas

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

Add InProcessBackend to run subagents in-process rather than via subprocess,

enabling faster initialization and better resource management for agent

collaboration arenas.

Key changes:

- Add InProcessBackend with sandboxed in-process agent execution

- Refactor agent runtime into headless vs interactive modes

- Add AsyncMessageQueue utility for agent message passing

- Update ArenaManager with backend selection (in-process vs subprocess)

- Refactor subagent types/exports; consolidate in subagents/types

- Remove deprecated agent-hooks.ts (functionality merged into runtime)

- Update task tool to support new agent lifecycle

Breaking: Subagent type exports restructured; import from subagents/types

packages/cli/src/ui/components/ArenaSelectDialog.tsx

@@ -9,7 +9,7 @@ import { useCallback, useMemo } from 'react';
 import { Box, Text } from 'ink';
 import {
   type ArenaManager,
-  ArenaAgentStatus,
+  AgentStatus,
   type Config,
 } from '@qwen-code/qwen-code-core';
 import { theme } from '../semantic-colors.js';
@@ -138,7 +138,7 @@ export function ArenaSelectDialog({
         // Build diff summary from cached result if available
         let diffAdditions = 0;
         let diffDeletions = 0;
-        if (agent.status === ArenaAgentStatus.COMPLETED && result) {
+        if (agent.status === AgentStatus.COMPLETED && result) {
           const agentResult = result.agents.find(
             (a) => a.agentId === agent.agentId,
           );
@@ -182,7 +182,7 @@ export function ArenaSelectDialog({
           value: agent.agentId,
           title,
           description,
-          disabled: agent.status !== ArenaAgentStatus.COMPLETED,
+          disabled: agent.status !== AgentStatus.COMPLETED,
         };
       }),
     [agents, result],