Merge upstream/main: sync latest updates

- feat(gateway): aggregate all text chunks in non-streaming Gemini responses
- feat(gateway): add SUGGESTION MODE request interception
- feat(oauth): support Anthropic Team accounts with sk authorization
- fix(oauth): update Anthropic OAuth parameters to sync with latest client
- feat: add PromoCodeEnabled setting (default: true)
- resolved conflict: keep TianShuAPI site name while adding PromoCode feature

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

frontend/src/api/admin/settings.ts

@@ -12,6 +12,7 @@ export interface SystemSettings {
   // Registration settings
   registration_enabled: boolean
   email_verify_enabled: boolean
+  promo_code_enabled: boolean
   // Default settings
   default_balance: number
   default_concurrency: number
@@ -64,6 +65,7 @@ export interface SystemSettings {
 export interface UpdateSettingsRequest {
   registration_enabled?: boolean
   email_verify_enabled?: boolean
+  promo_code_enabled?: boolean
   default_balance?: number
   default_concurrency?: number
   site_name?: string