feat: 升级至 v0.2.3 — Token 估算优化、工具确认超时改进、工作空间标签页

1. Token 估算优化（核心改进）：新增 token-estimator.ts 智能字符估算（中文 1.5 token/字、ASCII 0.25 token/字），替换三处旧的 length/2 粗略估算，中文场景准确度从 ~50% 提升到 ~90%

2. 工具确认超时改进：超时时间可配置（30s~600s）、超时 toast 通知、ConfirmationDialog 倒计时 UI（进度条 + 最后 10 秒红色脉冲动画）、SettingsModal 新增配置入口

3. 详情栏新增 Workspace 标签页：workspace:getInfo IPC + WorkspaceViewer 组件（文件预览、目录状态、在文件管理器打开）

electron/harness/prompts/context-builder.ts

@@ -17,6 +17,7 @@
 
 import type { MetonaContext, MetonaMemoryItem, MetonaMessage, MetonaSystemPrompt, MetonaToolDef } from '../types';
 import type { WorkspaceFiles } from '../../services/workspace.service';
+import { estimateStringTokens } from '../utils/token-estimator';
 
 interface ContextBuildParams {
   userInput: string;
@@ -245,6 +246,8 @@ Use tools when needed to gather information or perform actions. Think step by st
 
   /**
    * Token 估算
+   * 使用智能字符估算：中文 1.5 token/字，ASCII 0.25 token/字，其他 1 token/字
+   * @see electron/harness/utils/token-estimator.ts
    */
   private estimateTokens(
     history: MetonaMessage[],
@@ -256,22 +259,24 @@ Use tools when needed to gather information or perform actions. Think step by st
     let total = 0;
 
     // System Prompt
-    total += Math.ceil((systemPrompt.roleDefinition?.length ?? 0) / 2);
-    total += Math.ceil((systemPrompt.outputConstraints?.length ?? 0) / 2);
-    total += Math.ceil((systemPrompt.safetyGuidelines?.length ?? 0) / 2);
-    total += Math.ceil((systemPrompt.dynamicReminders?.length ?? 0) / 2);
+    total += estimateStringTokens(systemPrompt.roleDefinition ?? '');
+    total += estimateStringTokens(systemPrompt.outputConstraints ?? '');
+    total += estimateStringTokens(systemPrompt.safetyGuidelines ?? '');
+    total += estimateStringTokens(systemPrompt.dynamicReminders ?? '');
 
-    // 历史消息
-    for (const msg of history) total += Math.ceil(msg.content.length / 2);
+    // 历史消息（每条加 4 token 结构性开销）
+    for (const msg of history) {
+      total += estimateStringTokens(msg.content) + 4;
+    }
 
     // 记忆
-    for (const mem of memories) total += Math.ceil(mem.content.length / 2);
+    for (const mem of memories) total += estimateStringTokens(mem.content);
 
     // 工具定义
-    for (const tool of tools) total += Math.ceil((tool.name.length + tool.description.length) / 2);
+    for (const tool of tools) total += estimateStringTokens(tool.name + tool.description);
 
     // 用户输入
-    total += Math.ceil(userInput.length / 2);
+    total += estimateStringTokens(userInput);
 
     return total;
   }