feat: add Cache TTL Override per account + bump VERSION to 0.1.83

- Account-level cache TTL override: rewrite Anthropic cache_creation
  token classification (5m↔1h) in streaming/non-streaming responses
- New DB field cache_ttl_overridden in usage_log for billing tracking
- Migration 055_add_cache_ttl_overridden
- Frontend: CacheTTL override toggle in account create/edit modals
- Ent schema regenerated for new usage_log fields

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/types/index.ts

@@ -614,6 +614,10 @@ export interface Account {
   // 启用后将在15分钟内固定 metadata.user_id 中的 session ID
   session_id_masking_enabled?: boolean | null
 
+  // 缓存 TTL 强制替换（仅 Anthropic OAuth/SetupToken 账号有效）
+  cache_ttl_override_enabled?: boolean | null
+  cache_ttl_override_target?: string | null
+
   // 运行时状态（仅当启用对应限制时返回）
   current_window_cost?: number | null // 当前窗口费用
   active_sessions?: number | null // 当前活跃会话数
@@ -827,6 +831,9 @@ export interface UsageLog {
   // User-Agent
   user_agent: string | null
 
+  // Cache TTL Override
+  cache_ttl_overridden: boolean
+
   created_at: string
 
   user?: User