refactor: 统一权限检查逻辑，使用 apiKeyService.hasPermission

将散布在各处的权限检查逻辑（permissions || 'all'）统一为
apiKeyService.hasPermission() 方法调用，确保：

- 权限检查的唯一真实来源
- 避免默认值不一致导致的安全问题
- 便于后续权限模型的扩展和维护

影响文件：
- geminiHandlers.js: key-info 端点
- apiStats.js: user-stats 统计端点
- openaiClaudeRoutes.js: 权限校验辅助函数
- openaiRoutes.js: key-info 端点

src/handlers/geminiHandlers.js

@@ -862,7 +862,7 @@ async function handleKeyInfo(req, res) {
     res.json({
       id: keyData.id,
       name: keyData.name,
-      permissions: keyData.permissions || 'all',
+      permissions: keyData.permissions,
       token_limit: keyData.tokenLimit,
       tokens_used: keyData.usage.total.tokens,
       tokens_remaining:

src/routes/apiStats.js

@@ -155,7 +155,7 @@ router.post('/api/user-stats', async (req, res) => {
         restrictedModels,
         enableClientRestriction: keyData.enableClientRestriction === 'true',
         allowedClients,
-        permissions: keyData.permissions || 'all',
+        permissions: keyData.permissions,
         // 添加激活相关字段
         expirationMode: keyData.expirationMode || 'fixed',
         isActivated: keyData.isActivated === 'true',

src/routes/openaiClaudeRoutes.js

@@ -20,8 +20,7 @@ const { getEffectiveModel } = require('../utils/modelHelper')
 
 // 🔧 辅助函数：检查 API Key 权限
 function checkPermissions(apiKeyData, requiredPermission = 'claude') {
-  const permissions = apiKeyData.permissions || 'all'
-  return permissions === 'all' || permissions === requiredPermission
+  return apiKeyService.hasPermission(apiKeyData?.permissions, requiredPermission)
 }
 
 function queueRateLimitUpdate(rateLimitInfo, usageSummary, model, context = '') {

src/routes/openaiRoutes.js

@@ -904,7 +904,7 @@ router.get('/key-info', authenticateApiKey, async (req, res) => {
       id: keyData.id,
       name: keyData.name,
       description: keyData.description,
-      permissions: keyData.permissions || 'all',
+      permissions: keyData.permissions,
       token_limit: keyData.tokenLimit,
       tokens_used: keyData.usage.total.tokens,
       tokens_remaining: