feat(channel): 缓存扁平化 + 网关映射集成 + 计费模式统一 + 模型限制

- 缓存重构为 O(1) 哈希结构 (pricingByGroupModel, mappingByGroupModel)
- 渠道模型映射接入网关流程 (Forward 前应用, a→b→c 映射链)
- 新增 billing_model_source 配置 (请求模型/最终模型计费)
- usage_logs 新增 channel_id, model_mapping_chain, billing_tier 字段
- 每种计费模式统一支持默认价格 + 区间定价
- 渠道模型限制开关 (restrict_models)
- 分组按平台分类展示 + 彩色图标
- 必填字段红色星号 + 模型映射 UI
- 去除模型通配符支持

frontend/src/i18n/locales/en.ts

@@ -1770,8 +1770,8 @@ export default {
         inOtherChannel: 'In "{name}"',
         modelPricing: 'Model Pricing',
         models: 'Models',
-        modelsPlaceholder: 'Type model name and press Enter. Supports wildcard *',
-        modelInputHint: 'Press Enter to add. Supports paste and wildcard *.',
+        modelsPlaceholder: 'Type full model name and press Enter',
+        modelInputHint: 'Press Enter to add, supports paste for batch import.',
         billingMode: 'Billing Mode',
         defaultPrices: 'Default prices (fallback when no interval matches)',
         inputPrice: 'Input',
@@ -1790,7 +1790,23 @@ export default {
         noPricingRules: 'No pricing rules yet. Click "Add" to create one.',
         perRequestPrice: 'Price per Request',
         tierLabel: 'Tier',
-        resolution: 'Resolution'
+        resolution: 'Resolution',
+        modelMapping: 'Model Mapping',
+        modelMappingHint: 'Map request model names to actual model names. Runs before account-level mapping.',
+        noMappingRules: 'No mapping rules. Click "Add" to create one.',
+        mappingSource: 'Source model',
+        mappingTarget: 'Target model',
+        billingModelSource: 'Billing Model',
+        billingModelSourceRequested: 'Bill by requested model',
+        billingModelSourceUpstream: 'Bill by final upstream model',
+        billingModelSourceHint: 'Controls which model name is used for pricing lookup',
+        selectedCount: '{count} selected',
+        searchGroups: 'Search groups...',
+        noGroupsMatch: 'No groups match your search',
+        restrictModels: 'Restrict Models',
+        restrictModelsHint: 'When enabled, only models in the pricing list are allowed. Others will be rejected.',
+        defaultPerRequestPrice: 'Default per-request price (fallback when no tier matches)',
+        defaultImagePrice: 'Default image price (fallback when no tier matches)'
       }
     },
 

frontend/src/i18n/locales/zh.ts

@@ -1850,8 +1850,8 @@ export default {
         inOtherChannel: '已属于「{name}」',
         modelPricing: '模型定价',
         models: '模型列表',
-        modelsPlaceholder: '输入模型名后按回车添加，支持通配符 *',
-        modelInputHint: '按回车添加，支持粘贴批量导入，支持通配符 *',
+        modelsPlaceholder: '输入完整模型名后按回车添加',
+        modelInputHint: '按回车添加，支持粘贴批量导入',
         billingMode: '计费模式',
         defaultPrices: '默认价格（未命中区间时使用）',
         inputPrice: '输入',
@@ -1870,7 +1870,23 @@ export default {
         noPricingRules: '暂无定价规则，点击"添加"创建',
         perRequestPrice: '单次价格',
         tierLabel: '层级',
-        resolution: '分辨率'
+        resolution: '分辨率',
+        modelMapping: '模型映射',
+        modelMappingHint: '将请求中的模型名映射为实际模型名。在账号级别映射之前执行。',
+        noMappingRules: '暂无映射规则，点击"添加"创建',
+        mappingSource: '源模型',
+        mappingTarget: '目标模型',
+        billingModelSource: '计费模型',
+        billingModelSourceRequested: '以请求模型计费',
+        billingModelSourceUpstream: '以最终模型计费',
+        billingModelSourceHint: '控制使用哪个模型名称进行定价查找',
+        selectedCount: '已选 {count} 个',
+        searchGroups: '搜索分组...',
+        noGroupsMatch: '没有匹配的分组',
+        restrictModels: '限制模型',
+        restrictModelsHint: '开启后，仅允许模型定价列表中的模型。不在列表中的模型请求将被拒绝。',
+        defaultPerRequestPrice: '默认单次价格（未命中层级时使用）',
+        defaultImagePrice: '默认图片价格（未命中层级时使用）'
       }
     },