feat: 添加对话压缩功能和上下文使用情况显示

- 新增 context 模块实现 Prune 和 Compaction 压缩策略
- Prune: 将旧工具调用结果替换为占位符
- Compaction: 使用 AI 生成对话摘要
- CLI 提示符显示上下文使用量 [used/available]
- 添加 /compact 命令手动压缩对话
- 添加 /context 命令查看上下文详情
- Agent 集成自动压缩 (85%阈值) 和强制压缩功能

src/ui/terminal.ts

@@ -28,14 +28,36 @@ export class TerminalUI {
     console.log(chalk.cyan('║') + chalk.gray('     Powered by DeepSeek / Claude      ') + chalk.cyan('║'));
     console.log(chalk.cyan('╚════════════════════════════════════════╝\n'));
     console.log(chalk.gray('输入你的问题，或使用以下命令：'));
-    console.log(chalk.yellow('  /help') + chalk.gray('  - 显示帮助'));
-    console.log(chalk.yellow('  /clear') + chalk.gray(' - 清空对话历史'));
-    console.log(chalk.yellow('  /exit') + chalk.gray('  - 退出程序'));
+    console.log(chalk.yellow('  /help') + chalk.gray('    - 显示帮助'));
+    console.log(chalk.yellow('  /clear') + chalk.gray('   - 清空对话历史'));
+    console.log(chalk.yellow('  /compact') + chalk.gray(' - 压缩对话历史'));
+    console.log(chalk.yellow('  /context') + chalk.gray(' - 查看上下文使用情况'));
+    console.log(chalk.yellow('  /exit') + chalk.gray('    - 退出程序'));
     console.log('');
   }
 
+  // 格式化上下文使用情况（带颜色）
+  private formatContextUsage(): string {
+    const usage = this.agent.getContextUsage();
+    const percent = usage.usagePercent;
+
+    // 根据使用率选择颜色
+    let colorFn: (text: string) => string;
+    if (percent < 50) {
+      colorFn = chalk.green;
+    } else if (percent < 80) {
+      colorFn = chalk.yellow;
+    } else {
+      colorFn = chalk.red;
+    }
+
+    const used = usage.input >= 1000 ? `${(usage.input / 1000).toFixed(1)}k` : `${usage.input}`;
+    const limit = `${(usage.available / 1000).toFixed(0)}k`;
+    return colorFn(`[${used}/${limit}]`);
+  }
+
   // 处理特殊命令
-  private handleCommand(input: string): boolean {
+  private async handleCommand(input: string): Promise<boolean> {
     const command = input.toLowerCase().trim();
 
     switch (command) {
@@ -47,14 +69,52 @@ export class TerminalUI {
         console.log(chalk.gray('  • 搜索代码'));
         console.log(chalk.gray('  • 回答编程问题'));
         console.log('');
+        console.log(chalk.white('  命令：'));
+        console.log(chalk.gray('  • /help    - 显示此帮助'));
+        console.log(chalk.gray('  • /clear   - 清空对话历史'));
+        console.log(chalk.gray('  • /compact - 压缩对话历史，释放上下文空间'));
+        console.log(chalk.gray('  • /context - 显示当前上下文使用情况'));
+        console.log(chalk.gray('  • /exit    - 退出程序'));
+        console.log('');
         return true;
 
       case '/clear':
-        // clearHistory 现在是异步的
-        void this.agent.clearHistory();
+        await this.agent.clearHistory();
         console.log(chalk.green('✓ 对话历史已清空\n'));
         return true;
 
+      case '/compact':
+        console.log(chalk.yellow('正在压缩对话历史...\n'));
+        try {
+          const beforeUsage = this.agent.getContextUsage();
+          const result = await this.agent.compactHistory();
+          const afterUsage = this.agent.getContextUsage();
+
+          if (result.freedTokens > 0) {
+            console.log(chalk.green(`✓ 压缩完成！`));
+            console.log(chalk.gray(`  策略: ${result.type}`));
+            console.log(chalk.gray(`  释放: ${(result.freedTokens / 1000).toFixed(1)}k tokens`));
+            console.log(chalk.gray(`  之前: ${(beforeUsage.input / 1000).toFixed(1)}k`));
+            console.log(chalk.gray(`  之后: ${(afterUsage.input / 1000).toFixed(1)}k`));
+          } else {
+            console.log(chalk.yellow('没有可压缩的内容'));
+          }
+          console.log('');
+        } catch (error) {
+          console.log(chalk.red(`压缩失败: ${error instanceof Error ? error.message : String(error)}\n`));
+        }
+        return true;
+
+      case '/context':
+        const usage = this.agent.getContextUsage();
+        console.log(chalk.cyan('\n📊 上下文使用情况：'));
+        console.log(chalk.gray(`  已使用: ${(usage.input / 1000).toFixed(1)}k tokens`));
+        console.log(chalk.gray(`  可用: ${(usage.available / 1000).toFixed(0)}k tokens`));
+        console.log(chalk.gray(`  上下文限制: ${(usage.contextLimit / 1000).toFixed(0)}k tokens`));
+        console.log(chalk.gray(`  使用率: ${usage.usagePercent.toFixed(1)}%`));
+        console.log('');
+        return true;
+
       case '/exit':
       case '/quit':
         console.log(chalk.cyan('\n👋 再见！\n'));
@@ -74,7 +134,9 @@ export class TerminalUI {
         return;
       }
 
-      this.rl.question(chalk.green('You > '), (answer) => {
+      // 显示带上下文使用情况的提示符
+      const contextInfo = this.formatContextUsage();
+      this.rl.question(`${contextInfo} ${chalk.green('You >')} `, (answer) => {
         resolve(answer ?? '');
       });
     });
@@ -95,7 +157,7 @@ export class TerminalUI {
 
         // 处理命令
         if (input.startsWith('/')) {
-          if (this.handleCommand(input)) {
+          if (await this.handleCommand(input)) {
             continue;
           }
         }