feat: Agent Office — AI 에이전트 가상 오피스 (#2)

## Summary
- Canvas 2D 픽셀아트 오피스 렌더링 (SpriteSheet + TileMap + AgentSprite)
- WebSocket 실시간 에이전트 상태 동기화 (useAgentManager)
- ChatPanel (명령/승인) + TaskHistory (작업 이력) UI
- 다크 테마 + glassmorphism 패널

## Changes (7 commits)
- API helpers + route + Lab entry
- Canvas engine: SpriteSheet, TileMap, AgentSprite, OfficeRenderer
- React hooks: useAgentManager, useOfficeCanvas
- Components: ChatPanel, TaskHistory
- Main page + CSS
- Code review fixes: claude agent 참조 제거, rejected 배지 추가

Reviewed-on: #2

src/pages/agent-office/hooks/useAgentManager.js

@@ -0,0 +1,88 @@
+import { useState, useEffect, useRef, useCallback } from 'react';
+
+export function useAgentManager() {
+  const [agents, setAgents] = useState({});
+  const [pendingTasks, setPendingTasks] = useState([]);
+  const [connected, setConnected] = useState(false);
+  const wsRef = useRef(null);
+  const reconnectTimer = useRef(null);
+
+  const connect = useCallback(() => {
+    const protocol = window.location.protocol === 'https:' ? 'wss:' : 'ws:';
+    const wsUrl = `${protocol}//${window.location.host}/api/agent-office/ws`;
+
+    const ws = new WebSocket(wsUrl);
+    wsRef.current = ws;
+
+    ws.onopen = () => {
+      setConnected(true);
+      if (reconnectTimer.current) clearTimeout(reconnectTimer.current);
+    };
+
+    ws.onclose = () => {
+      setConnected(false);
+      reconnectTimer.current = setTimeout(connect, 3000);
+    };
+
+    ws.onerror = () => { ws.close(); };
+
+    ws.onmessage = (event) => {
+      const msg = JSON.parse(event.data);
+
+      switch (msg.type) {
+        case 'init': {
+          const agentMap = {};
+          for (const a of msg.agents) {
+            agentMap[a.agent_id] = { state: a.state, detail: a.detail };
+          }
+          setAgents(agentMap);
+          setPendingTasks(msg.pending || []);
+          break;
+        }
+        case 'agent_state':
+          setAgents(prev => ({
+            ...prev,
+            [msg.agent]: { state: msg.state, detail: msg.detail, taskId: msg.task_id },
+          }));
+          break;
+        case 'task_complete':
+          setAgents(prev => ({
+            ...prev,
+            [msg.agent]: { ...prev[msg.agent], lastResult: msg.result },
+          }));
+          setPendingTasks(prev => prev.filter(id => id !== msg.task_id));
+          break;
+        case 'command_result':
+          setAgents(prev => ({
+            ...prev,
+            [msg.agent]: { ...prev[msg.agent], lastCommand: msg.result },
+          }));
+          break;
+        default:
+          break;
+      }
+    };
+  }, []);
+
+  useEffect(() => {
+    connect();
+    return () => {
+      if (wsRef.current) wsRef.current.close();
+      if (reconnectTimer.current) clearTimeout(reconnectTimer.current);
+    };
+  }, [connect]);
+
+  const sendCommand = useCallback((agent, action, params = {}) => {
+    if (wsRef.current?.readyState === WebSocket.OPEN) {
+      wsRef.current.send(JSON.stringify({ type: 'command', agent, action, params }));
+    }
+  }, []);
+
+  const sendApproval = useCallback((agent, taskId, approved) => {
+    if (wsRef.current?.readyState === WebSocket.OPEN) {
+      wsRef.current.send(JSON.stringify({ type: 'approval', agent, task_id: taskId, approved }));
+    }
+  }, []);
+
+  return { agents, pendingTasks, connected, sendCommand, sendApproval };
+}