fix: DevTools auto npm install for frontend on Windows

Two-part fix for frontend startup failure:
1. Check .package-lock.json as install-complete marker instead of
   just node_modules directory existence, and delete corrupt
   node_modules before reinstalling
2. Bypass npm.cmd batch file on Windows — use node with full path
   to npm-cli.js to avoid module resolution conflicts when cwd
   contains a node_modules directory

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

devtools/src/process-manager.js

@@ -169,6 +169,33 @@ class ProcessManager extends EventEmitter {
       args = svc.args || [];
     }
 
+    // 对使用 npm 的服务，检查 node_modules 是否完整
+    if (svc.command === 'npx' || svc.command === 'node') {
+      const modulesDir = path.join(svc.cwd, 'node_modules');
+      const installMarker = path.join(modulesDir, '.package-lock.json');
+      if (!fs.existsSync(installMarker)) {
+        // 如果 node_modules 目录存在但不完整，先删除
+        if (fs.existsSync(modulesDir)) {
+          this.emit('log', serviceId, 'system', 'node_modules 不完整，正在清理...');
+          fs.rmSync(modulesDir, { recursive: true, force: true });
+        }
+        this.emit('log', serviceId, 'system', '正在运行 npm install...');
+        // Windows: npm.cmd batch file has module resolution issues when
+        // cwd has a node_modules directory, even if empty. Use node+npm-cli.js directly.
+        const installCmd = isWin
+          ? `"${process.execPath}" "${path.join(path.dirname(process.execPath), 'node_modules/npm/bin/npm-cli.js')}" install`
+          : 'npm install';
+        try {
+          execSync(installCmd, { cwd: svc.cwd, timeout: 120000, stdio: 'pipe' });
+          this.emit('log', serviceId, 'system', 'npm install 完成');
+        } catch (err) {
+          const stderr = err.stderr?.toString() || err.message;
+          this.emit('log', serviceId, 'error', `npm install 失败: ${stderr}`);
+          throw new Error(`npm install 失败: ${stderr}`);
+        }
+      }
+    }
+
     const env = { ...process.env, ...svc.env };
     // .cmd/.bat on Windows needs shell:true
     const needsShell = isWin && (command.endsWith('.cmd') || command.endsWith('.bat'));