feat(agent-office): AI 토큰 사용량 뱃지 표시

- api.js: getAgentTokenUsage 헬퍼 추가
- AgentColumn: 헤더에 오늘 토큰 사용량 뱃지 (🧮 N,NNN)
- 30초 폴링 + state 변경 시 즉시 갱신

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/pages/agent-office/components/AgentColumn.jsx

@@ -1,5 +1,5 @@
 import React, { useState, useEffect } from 'react';
-import { getAgentTasks } from '../../../api';
+import { getAgentTasks, getAgentTokenUsage } from '../../../api';
 
 const STATUS_BADGE = {
   pending: { label: '대기', bg: '#92400e' },
@@ -26,6 +26,7 @@ const AgentColumn = ({ agentId, meta, agentState, notification, onCommand, onApp
   const [tasks, setTasks] = useState([]);
   const [input, setInput] = useState('');
   const [activeCommand, setActiveCommand] = useState(null);
+  const [tokenUsage, setTokenUsage] = useState(null);
 
   const state = agentState || { state: 'offline' };
   const commands = AGENT_COMMANDS[agentId] || [];
@@ -45,6 +46,22 @@ const AgentColumn = ({ agentId, meta, agentState, notification, onCommand, onApp
     }
   }, [agentId, state.state, state.detail]);
 
+  // 오늘자 AI 토큰 사용량 폴링 (30초 간격 + 작업 완료 시 즉시 갱신)
+  useEffect(() => {
+    let cancelled = false;
+    const fetchUsage = () => {
+      getAgentTokenUsage(agentId, 1)
+        .then(d => { if (!cancelled) setTokenUsage(d); })
+        .catch(() => {});
+    };
+    fetchUsage();
+    const interval = setInterval(fetchUsage, 30000);
+    return () => {
+      cancelled = true;
+      clearInterval(interval);
+    };
+  }, [agentId, state.state, state.detail]);
+
   const handleQuickAction = (cmd) => {
     if (cmd.needsInput) {
       setActiveCommand(cmd.action);
@@ -67,6 +84,14 @@ const AgentColumn = ({ agentId, meta, agentState, notification, onCommand, onApp
     <div className="ao-col" onClick={onClearNotification}>
       <div className="ao-col-header" style={{ borderColor: meta.color }}>
         <span className="ao-col-name" style={{ color: meta.color }}>{meta.name}</span>
+        {tokenUsage && tokenUsage.total_tokens > 0 && (
+          <span
+            className="ao-col-tokens"
+            title={`오늘 ${tokenUsage.task_count}건 작업 · ${tokenUsage.total_tokens.toLocaleString()} 토큰`}
+          >
+            🧮 {tokenUsage.total_tokens.toLocaleString()}
+          </span>
+        )}
         <span className={`ao-col-state ao-col-state--${state.state}`}>{state.state}</span>
         {notification > 0 && <span className="ao-col-badge">{notification}</span>}
       </div>