feat: 工作空间与 AI Tool Calling 深度集成

核心变更：
- 新增 execWorkspaceCommand() 无超时进程执行（workspace.ts）
- 新增 workspace:execTool IPC 通道（无超时，5MB 输出上限）
- run_command 工具改用 workspace IPC，移除 30s 超时限制
- run_command 默认启用（需用户确认），AI 上下文注入工作空间目录
- Agent Loop 工具执行：run_command 无超时，其他工具保持 30s
- Agent 系统提示词新增工作空间规则（userTerminated/truncated 反馈）

UI 修复：
- Header z-index 提升至 50，Model Bar 提升至 40，Input Area 提升至 30
- 工作空间面板 top 调整为 90px（header + model-bar），不再遮挡菜单
- Input Area 增加 position: relative 确保 z-index 生效

其他：
- 新增 docs/DEVELOPMENT.md 开发规范文档
- 设置面板 run_command 开关文案优化，默认值改为 true

src/main/workspace.ts

@@ -200,3 +200,137 @@ export function isProcessAlive(id: string): boolean {
 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
+): 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 shellArgs = isWin ? ['/c', command] : ['-c', command];
+      const proc = spawn(shell, shellArgs, {
+        cwd: workDir,
+        env: { ...process.env, ...(isWin ? {} : { TERM: 'xterm-256color' }) },
+        stdio: ['pipe', 'pipe', 'pipe']
+      });
+
+      activeProcesses.set(cmdId, proc);
+
+      proc.stdout.on('data', (data: Buffer) => {
+        if (stdoutBuf.length < MAX_OUTPUT) {
+          stdoutBuf += data.toString();
+          if (stdoutBuf.length > MAX_OUTPUT) {
+            stdoutBuf = stdoutBuf.slice(0, MAX_OUTPUT);
+            truncated = true;
+          }
+        } else {
+          truncated = true;
+        }
+      });
+
+      proc.stderr.on('data', (data: Buffer) => {
+        if (stderrBuf.length < MAX_OUTPUT) {
+          stderrBuf += data.toString();
+          if (stderrBuf.length > MAX_OUTPUT) {
+            stderrBuf = stderrBuf.slice(0, MAX_OUTPUT);
+            truncated = true;
+          }
+        } else {
+          truncated = true;
+        }
+      });
+
+      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);
+}