feat: add model plaza with group-scoped pricing showcase

- public /model-plaza page (standalone + admin-embedded) listing groups
  with discounted effective prices alongside LiteLLM official reference
- faceted platform/group/rate filters: cross-dimension options gray out
  instead of disappearing, platform-tinted chips via accent color-mix
- paid-price columns highlighted with per-platform tint band
- OptionalJWT middleware so anonymous and signed-in users share one route
- admin settings: enable switch, require-auth switch, markdown description

frontend/src/api/admin/settings.ts

@@ -659,6 +659,11 @@ export interface SystemSettings {
   // Available Channels feature switch
   available_channels_enabled: boolean;
 
+  // Model Plaza feature switches + description
+  model_plaza_enabled: boolean;
+  model_plaza_require_auth: boolean;
+  model_plaza_description: string;
+
   // Affiliate (邀请返利) feature switch
   affiliate_enabled: boolean;
 
@@ -930,6 +935,11 @@ export interface UpdateSettingsRequest {
   // Available Channels feature switch
   available_channels_enabled?: boolean;
 
+  // Model Plaza feature switches + description
+  model_plaza_enabled?: boolean;
+  model_plaza_require_auth?: boolean;
+  model_plaza_description?: string;
+
   // Affiliate (邀请返利) feature switch
   affiliate_enabled?: boolean;
 

frontend/src/api/modelPlaza.ts

@@ -0,0 +1,62 @@
+/**
+ * Model Plaza API（公开端点，可匿名访问）
+ * 以分组为中心的模型价目：分组信息 + 模型渠道定价 + LiteLLM 官方参考价。
+ * 带 token 请求时后端会额外返回专属分组与用户专属倍率。
+ */
+
+import { apiClient } from './client'
+import type { UserSupportedModelPricing } from './channels'
+
+/** LiteLLM 官方参考价（USD per token，字段缺失 = 官方数据未覆盖）。 */
+export interface PlazaOfficialPricing {
+  input_price: number | null
+  output_price: number | null
+  /** 5m 缓存写入（= LiteLLM cache_creation）。 */
+  cache_write_price: number | null
+  /** 1h 缓存写入（LiteLLM cache_creation_above_1hr），多数模型缺失。 */
+  cache_write_1h_price?: number | null
+  cache_read_price: number | null
+}
+
+export interface PlazaModel {
+  name: string
+  platform: string
+  pricing: UserSupportedModelPricing | null
+  official_pricing: PlazaOfficialPricing | null
+}
+
+export interface ModelPlazaGroup {
+  id: number
+  name: string
+  description: string
+  platform: string
+  /** 'standard' | 'subscription' */
+  subscription_type: string
+  rate_multiplier: number
+  /** 登录且管理员为该用户配了专属倍率时返回；生效倍率 = user_rate ?? rate_multiplier。 */
+  user_rate_multiplier?: number
+  peak_rate_enabled: boolean
+  peak_start: string
+  peak_end: string
+  peak_rate_multiplier: number
+  is_exclusive: boolean
+  models: PlazaModel[]
+}
+
+export interface ModelPlazaResponse {
+  /** 管理员配置的全局价格说明（Markdown）。 */
+  description: string
+  groups: ModelPlazaGroup[]
+}
+
+/** 获取模型广场数据。开关未启用时后端返回 404。 */
+export async function getModelPlaza(options?: { signal?: AbortSignal }): Promise<ModelPlazaResponse> {
+  const { data } = await apiClient.get<ModelPlazaResponse>('/model-plaza', {
+    signal: options?.signal
+  })
+  return data
+}
+
+export const modelPlazaAPI = { getModelPlaza }
+
+export default modelPlazaAPI