refactor(models): unify provider metadata around backend catalog (#2896)

* feat(models): unify provider metadata around backend catalog

- Move shared provider metadata and alias normalization into backend-owned provider catalog
- Expose display, fetch, auth, and default model metadata through /api/models provider_options
- Replace frontend static provider registry with catalog-driven selection, validation, grouping, and fallback rendering
- Treat provider default api_base as placeholder and effective fetch/test base while keep submitted api_base separate from derived defaults
- Add model page retry handling, touched locale updates, and provider metadata assertions in backend tests

* fix(models): canonicalize backend provider aliases and common models

* fix(models): restore deepseek common model recommendations

web/frontend/src/api/models.ts

@@ -36,12 +36,20 @@ export interface ModelInfo {
 
 export interface ModelProviderOption {
   id: string
+  display_name?: string
+  icon_slug?: string
+  domain?: string
   default_api_base: string
   empty_api_key_allowed: boolean
   create_allowed: boolean
   default_model_allowed: boolean
+  supports_fetch?: boolean
   default_auth_method?: string
   auth_method_locked?: boolean
+  local?: boolean
+  priority?: number
+  common_models?: string[]
+  aliases?: string[]
 }
 
 interface ModelsListResponse {