refactor: 全面清理死代码 — 删除 348 行无用代码

删除文件:
- training-export.ts: 训练数据导出（零引用，UI 已移除）

删除函数:
- workspace.ts: isProcessAlive, getActiveProcessCount, execWorkspaceCommand, terminateWorkspaceCommand
- sqlite.ts: deleteMessagesBySession, getSkill, closeDatabase
- tool-registry.ts: isToolEnabled
- cron-manager.ts: clearAllTimers
- workspace-panel.ts: setOnToolTerminated, setWorkspaceDirPath

删除 UI:
- index.html: 训练数据导出按钮及说明
- settings-modal.ts: 训练数据导出事件绑定

src/main/workspace.ts

@@ -199,161 +199,3 @@ export function listWorkspaceDir(dirPath?: string): { success: boolean; entries?
     return { success: false, error: (err as Error).message };
   }
 }
-
-/** 检查进程是否还活着 */
-export function isProcessAlive(id: string): boolean {
-  return activeProcesses.has(id);
-}
-
-/** 获取活跃进程数量 */
-export function getActiveProcessCount(): number {
-  return activeProcesses.size;
-}
-
-/**
- * 执行命令并收集完整输出（无超时限制）
- * 用于 AI Tool Calling 集成，通过 IPC invoke/handle 调用
- * 返回完整的 stdout + stderr + exitCode
- */
-export function execWorkspaceCommand(
-  command: string,
-  cwd?: string,
-  onOutput?: (type: 'stdout' | 'stderr', data: string) => void
-): Promise<{ success: boolean; stdout: string; stderr: string; exitCode: number | null; duration: number; userTerminated: boolean; truncated: boolean }> {
-  return new Promise((resolve) => {
-    const workDir = cwd ? path.resolve(cwd) : _workspaceDir;
-    const cmdId = `_tool_${Date.now()}_${Math.random().toString(36).slice(2, 8)}`;
-
-    // 安全检查
-    const cmdCheck = checkCommandAllowed(command);
-    if (!cmdCheck.ok) {
-      sendLog('warn', `🔧 工具命令被拦截`, `${command.slice(0, 100)} | ${cmdCheck.reason}`);
-      resolve({ success: false, stdout: '', stderr: cmdCheck.reason!, exitCode: 1, duration: 0, userTerminated: false, truncated: false });
-      return;
-    }
-
-    const dirCheck = checkPathAllowed(workDir, 'read');
-    if (!dirCheck.ok) {
-      sendLog('warn', `🔧 工具目录被拦截`, `${workDir} | ${dirCheck.reason}`);
-      resolve({ success: false, stdout: '', stderr: dirCheck.reason!, exitCode: 1, duration: 0, userTerminated: false, truncated: false });
-      return;
-    }
-
-    if (!fs.existsSync(workDir)) {
-      resolve({ success: false, stdout: '', stderr: `工作目录不存在: ${workDir}`, exitCode: 1, duration: 0, userTerminated: false, truncated: false });
-      return;
-    }
-
-    sendLog('info', `🔧 execWorkspaceCommand`, `${command.slice(0, 200)} | cwd: ${workDir}`);
-
-    const startTime = Date.now();
-    const MAX_OUTPUT = 5 * 1024 * 1024; // 5MB 输出上限
-    let stdoutBuf = '';
-    let stderrBuf = '';
-    let truncated = false;
-
-    try {
-      const isWin = process.platform === 'win32';
-      const shell = isWin ? 'cmd.exe' : 'bash';
-      const actualCmd = isWin ? `chcp 65001 >nul && ${command}` : command;
-      const shellArgs = isWin ? ['/c', actualCmd] : ['-c', actualCmd];
-      const proc = spawn(shell, shellArgs, {
-        cwd: workDir,
-        env: {
-          ...process.env,
-          ...(isWin ? {} : { TERM: 'xterm-256color' }),
-          LANG: 'en_US.UTF-8',
-          LC_ALL: 'en_US.UTF-8',
-          PYTHONIOENCODING: 'utf-8'
-        },
-        stdio: ['pipe', 'pipe', 'pipe']
-      });
-
-      activeProcesses.set(cmdId, proc);
-
-      proc.stdout.on('data', (data: Buffer) => {
-        const str = data.toString('utf-8');
-        if (stdoutBuf.length < MAX_OUTPUT) {
-          stdoutBuf += str;
-          if (stdoutBuf.length > MAX_OUTPUT) {
-            stdoutBuf = stdoutBuf.slice(0, MAX_OUTPUT);
-            truncated = true;
-          }
-        } else {
-          truncated = true;
-        }
-        // 实时推送到渲染进程
-        onOutput?.('stdout', str);
-      });
-
-      proc.stderr.on('data', (data: Buffer) => {
-        const str = data.toString('utf-8');
-        if (stderrBuf.length < MAX_OUTPUT) {
-          stderrBuf += str;
-          if (stderrBuf.length > MAX_OUTPUT) {
-            stderrBuf = stderrBuf.slice(0, MAX_OUTPUT);
-            truncated = true;
-          }
-        } else {
-          truncated = true;
-        }
-        // 实时推送到渲染进程
-        onOutput?.('stderr', str);
-      });
-
-      proc.on('close', (code) => {
-        activeProcesses.delete(cmdId);
-        const duration = Date.now() - startTime;
-        sendLog(
-          code === 0 ? 'success' : 'warn',
-          `🔧 execWorkspaceCommand 完成`,
-          `code: ${code} | ${duration}ms | stdout: ${stdoutBuf.length}B | stderr: ${stderrBuf.length}B`
-        );
-        resolve({
-          success: code === 0,
-          stdout: stdoutBuf,
-          stderr: stderrBuf,
-          exitCode: code,
-          duration,
-          userTerminated: false,
-          truncated
-        });
-      });
-
-      proc.on('error', (err) => {
-        activeProcesses.delete(cmdId);
-        const duration = Date.now() - startTime;
-        sendLog('error', `🔧 execWorkspaceCommand 失败`, `${cmdId} | ${err.message}`);
-        resolve({
-          success: false,
-          stdout: stdoutBuf,
-          stderr: stderrBuf + (stderrBuf ? '\n' : '') + `进程启动失败: ${err.message}`,
-          exitCode: 1,
-          duration,
-          userTerminated: false,
-          truncated
-        });
-      });
-    } catch (err) {
-      const duration = Date.now() - startTime;
-      sendLog('error', `🔧 execWorkspaceCommand 异常`, (err as Error).message);
-      resolve({
-        success: false,
-        stdout: stdoutBuf,
-        stderr: (err as Error).message,
-        exitCode: 1,
-        duration,
-        userTerminated: false,
-        truncated: false
-      });
-    }
-  });
-}
-
-/**
- * 终止 execWorkspaceCommand 启动的进程
- * @returns 是否成功终止
- */
-export function terminateWorkspaceCommand(commandId: string): boolean {
-  return killProcess(commandId);
-}