feat: header 增加当前会话总 token 消耗统计

- 新增 totalTokens 元素（帮助按钮右侧，🪙 图标 + 数字）
- chat-area.ts 新增 updateTotalTokens() 函数
- 四个触发点：新消息完成、新建会话、加载历史、应用初始化
- 数字自动格式化（toLocaleString）

src/renderer/components/chat-area.ts

@@ -384,6 +384,18 @@ export function enableAutoScroll(): void {
   if (scrollBtnEl) scrollBtnEl.style.display = 'none';
 }
 
+/** 统计当前会话总 token 消耗并更新 header 显示 */
+export function updateTotalTokens(): void {
+  const session = state.get<ChatSession | null>(KEYS.CURRENT_SESSION);
+  const el = document.querySelector('#totalTokensValue');
+  if (!el) return;
+  if (!session) { el.textContent = '0'; return; }
+  const total = session.messages
+    .filter(m => m.role === 'assistant' && m.eval_count)
+    .reduce((sum, m) => sum + (m.eval_count || 0), 0);
+  el.textContent = total > 0 ? total.toLocaleString() : '0';
+}
+
 // ── 导出功能 ──
 
 async function nativeSaveFile(defaultName: string, content: string): Promise<void> {

src/renderer/components/history-modal.ts

@@ -4,7 +4,7 @@
 
 import { state, KEYS } from '../state/state.js';
 import { debounce, escapeHtml, formatTime } from '../utils/utils.js';
-import { exportAsMarkdown, exportAsHtml, exportAsTxt, renderMessages, clearMessages } from './chat-area.js';
+import { exportAsMarkdown, exportAsHtml, exportAsTxt, renderMessages, clearMessages, updateTotalTokens } from './chat-area.js';
 import { showConfirm } from './prompt-modal.js';
 import { ChatDB } from '../db/chat-db.js';
 import { logSession, logWarn } from '../services/log-service.js';
@@ -181,6 +181,7 @@ async function loadHistorySession(sessionId: string): Promise<void> {
 
   clearMessages();
   renderMessages();
+  updateTotalTokens();
   closeHistoryModal();
 }
 

src/renderer/components/input-area.ts

@@ -7,7 +7,7 @@ import { detectLanguage, truncate, escapeHtml, formatSize } from '../utils/utils
 import { getSelectedModel, isThinkEnabled, isVisionAvailable, isToolCallingSupported } from './model-bar.js';
 import {
   renderMessages, appendAssistantPlaceholder, appendSystemMessage,
-  updateLastAssistantMessage, clearMessages, safeMarkdown, enableAutoScroll
+  updateLastAssistantMessage, clearMessages, safeMarkdown, enableAutoScroll, updateTotalTokens
 } from './chat-area.js';
 import { showToast } from './toast.js';
 import { isRagEnabled, performRagRetrieval } from './kb-modal.js';
@@ -521,6 +521,7 @@ export async function sendMessage(): Promise<void> {
     }
 
     await saveCurrentSession();
+    updateTotalTokens();
 
     // ── 自动提取记忆（非阻塞）──
     if (isMemoryEnabled() && freshSession.messages.length >= 6) {
@@ -738,6 +739,7 @@ async function sendMessageWithAgentLoop(text: string, currentSession: ChatSessio
         updateLastAssistantMessage(assistantContent, thinkContent || null, loopStats || null);
         renderMessages();
         await saveCurrentSession();
+        updateTotalTokens();
       }
     });
   } catch (err) {

src/renderer/index.html

@@ -34,6 +34,7 @@
                     <line x1="12" y1="17" x2="12.01" y2="17"/>
                 </svg>
             </button>
+            <span class="total-tokens" id="totalTokens" title="当前会话总 token 消耗">🪙 <span id="totalTokensValue">0</span></span>
         </div>
         <div class="header-right">
             <div class="conn-status pending" id="connStatus" title="连接状态">

src/renderer/main.ts

@@ -15,7 +15,7 @@ import { initToast, showToast } from './components/toast.js';
 import { initLightbox, closeLightbox } from './components/lightbox.js';
 import { initHeader, checkConnection } from './components/header.js';
 import { initModelBar, loadModels, setSelectedModel } from './components/model-bar.js';
-import { initChatArea, renderMessages, clearMessages, enableAutoScroll } from './components/chat-area.js';
+import { initChatArea, renderMessages, clearMessages, enableAutoScroll, updateTotalTokens } from './components/chat-area.js';
 import { initInputArea } from './components/input-area.js';
 import { initSettingsModal, closeSettingsModal } from './components/settings-modal.js';
 import { initHistoryModal, closeHistoryModal } from './components/history-modal.js';
@@ -148,6 +148,7 @@ async function startNewSession(): Promise<void> {
   clearMessages();
   enableAutoScroll();
   renderMessages();
+  updateTotalTokens();
   (document.querySelector('#chatInput') as HTMLElement)?.focus();
 }
 
@@ -242,6 +243,7 @@ async function init(): Promise<void> {
     state.set('memoryEnabled', memoryEnabled);
 
     (document.querySelector('#chatInput') as HTMLElement)?.focus();
+    updateTotalTokens();
 
     logSuccess('应用初始化完成');
   } catch (err) {

src/renderer/styles/style.css

@@ -369,6 +369,20 @@ html, body {
     opacity: 1;
 }
 
+.total-tokens {
+    display: inline-flex;
+    align-items: center;
+    gap: 4px;
+    margin-left: 8px;
+    padding: 2px 8px;
+    font-size: 11px;
+    color: var(--text-secondary);
+    background: var(--bg-subtle, rgba(255,255,255,0.04));
+    border-radius: 10px;
+    white-space: nowrap;
+    user-select: none;
+}
+
 /* ═══ 模型选择栏 ═══ */
 .model-bar {
     display: flex;