feat: 添加联系我们配置接口和字典配置缓存

1. 新增DictionaryItem字典配置结构体
2. 添加字典配置缓存及失效逻辑
3. 实现联系我们接口的业务逻辑和测试用例
4. 注册联系我们API路由
5. 集成字典配置到admin内部客户端
6. 处理字典配置更新的kafka事件

server/store/config_cache.go

@@ -60,6 +60,7 @@ var (
 	tenantByIDCache         = newConfigCache[*types.Tenant]()
 	registrationSMSCache    = newConfigCache[bool]()
 	thirdPartyConfigCache   = newConfigCache[map[string]string]()
+	dictConfigCache         = newConfigCache[[]types.DictionaryItem]()
 	appReleaseConfigCache   = newConfigCache[*types.AppRelease]()
 	moderationProviderCache = newConfigCache[*types.ModerationProviderConfig]()
 	moderationPolicyCache   = newConfigCache[*types.ModerationPolicy]()
@@ -174,6 +175,29 @@ func InvalidateThirdPartyConfigCache(group string) {
 	thirdPartyConfigCache.mu.Unlock()
 }
 
+func dictConfigCacheKey(dictType string) string {
+	return strings.TrimSpace(dictType)
+}
+
+func cloneDictionaryItems(src []types.DictionaryItem) []types.DictionaryItem {
+	if src == nil {
+		return nil
+	}
+	dst := make([]types.DictionaryItem, len(src))
+	copy(dst, src)
+	return dst
+}
+
+// InvalidateDictionaryConfigCache clears cached dictionary config. An empty
+// type clears all dictionary entries.
+func InvalidateDictionaryConfigCache(dictType string) {
+	if strings.TrimSpace(dictType) == "" {
+		dictConfigCache.clear()
+		return
+	}
+	dictConfigCache.delete(strings.TrimSpace(dictType))
+}
+
 func formatTenantIDForCache(id types.TenantID) string {
 	return strconv.FormatInt(int64(id), 10)
 }