feat(admin-spa): 添加 API Key 标签管理功能

基于 PR #114 的功能需求，为新版 admin-spa 实现完整的标签系统：

后端改进：
- apiKeyService 支持标签的创建、查询和更新
- admin 路由添加标签验证和处理逻辑
- 标签以 JSON 数组形式存储在 Redis 中

前端功能：
- API Key 列表增加标签列，显示彩色标签徽章
- 添加标签筛选器，支持按标签过滤 API Keys
- 创建和编辑 API Key 时可添加/删除标签
- 标签输入支持 Enter 键快速添加
- 自动收集并排序所有可用标签

界面优化：
- 使用蓝色圆角标签样式，视觉清晰
- 无标签时显示"无标签"提示
- 标签管理操作流畅，支持即时添加删除

🤖 Generated with [Claude Code](https://claude.ai/code)

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

src/services/apiKeyService.js

@@ -27,7 +27,8 @@ class ApiKeyService {
       restrictedModels = [],
       enableClientRestriction = false,
       allowedClients = [],
-      dailyCostLimit = 0
+      dailyCostLimit = 0,
+      tags = []
     } = options;
 
     // 生成简单的API Key (64字符十六进制)
@@ -53,6 +54,7 @@ class ApiKeyService {
       enableClientRestriction: String(enableClientRestriction || false),
       allowedClients: JSON.stringify(allowedClients || []),
       dailyCostLimit: String(dailyCostLimit || 0),
+      tags: JSON.stringify(tags || []),
       createdAt: new Date().toISOString(),
       lastUsedAt: '',
       expiresAt: expiresAt || '',
@@ -82,6 +84,7 @@ class ApiKeyService {
       enableClientRestriction: keyData.enableClientRestriction === 'true',
       allowedClients: JSON.parse(keyData.allowedClients || '[]'),
       dailyCostLimit: parseFloat(keyData.dailyCostLimit || 0),
+      tags: JSON.parse(keyData.tags || '[]'),
       createdAt: keyData.createdAt,
       expiresAt: keyData.expiresAt,
       createdBy: keyData.createdBy
@@ -142,6 +145,14 @@ class ApiKeyService {
         allowedClients = [];
       }
 
+      // 解析标签
+      let tags = [];
+      try {
+        tags = keyData.tags ? JSON.parse(keyData.tags) : [];
+      } catch (e) {
+        tags = [];
+      }
+
       return {
         valid: true,
         keyData: {
@@ -163,6 +174,7 @@ class ApiKeyService {
           allowedClients: allowedClients,
           dailyCostLimit: parseFloat(keyData.dailyCostLimit || 0),
           dailyCost: dailyCost || 0,
+          tags: tags,
           usage
         }
       };
@@ -201,6 +213,11 @@ class ApiKeyService {
         } catch (e) {
           key.allowedClients = [];
         }
+        try {
+          key.tags = key.tags ? JSON.parse(key.tags) : [];
+        } catch (e) {
+          key.tags = [];
+        }
         delete key.apiKey; // 不返回哈希后的key
       }
 
@@ -220,12 +237,12 @@ class ApiKeyService {
       }
 
       // 允许更新的字段
-      const allowedUpdates = ['name', 'description', 'tokenLimit', 'concurrencyLimit', 'rateLimitWindow', 'rateLimitRequests', 'isActive', 'claudeAccountId', 'geminiAccountId', 'permissions', 'expiresAt', 'enableModelRestriction', 'restrictedModels', 'enableClientRestriction', 'allowedClients', 'dailyCostLimit'];
+      const allowedUpdates = ['name', 'description', 'tokenLimit', 'concurrencyLimit', 'rateLimitWindow', 'rateLimitRequests', 'isActive', 'claudeAccountId', 'geminiAccountId', 'permissions', 'expiresAt', 'enableModelRestriction', 'restrictedModels', 'enableClientRestriction', 'allowedClients', 'dailyCostLimit', 'tags'];
       const updatedData = { ...keyData };
 
       for (const [field, value] of Object.entries(updates)) {
         if (allowedUpdates.includes(field)) {
-          if (field === 'restrictedModels' || field === 'allowedClients') {
+          if (field === 'restrictedModels' || field === 'allowedClients' || field === 'tags') {
             // 特殊处理数组字段
             updatedData[field] = JSON.stringify(value || []);
           } else if (field === 'enableModelRestriction' || field === 'enableClientRestriction') {