feat(codex): add optional minimum quota reserve for pool scheduling

frontend/src/api/endpoints/types/provider.ts

@@ -822,6 +822,8 @@ export interface PoolAdvancedConfig {
   sticky_session_ttl_seconds?: number | null
   load_threshold_percent?: number | null
   skip_exhausted_accounts?: boolean | null
+  // Codex only: treat remaining quota <= 1% as exhausted (default false).
+  reserve_minimum_quota?: boolean
   // 旧字段（兼容读取）
   lru_enabled?: boolean
   scheduling_mode?: 'lru' | 'multi_score' | null