- Add subscription usage/expiry display at Profiles top (WPF/Avalonia)
- Parse `Subscription-Userinfo` header when updating subscriptions
- On startup and per-subscription auto-refresh, fetch header to update UI
- Persist last known usage to guiConfigs/SubUsage.json (atomic write)
- Unify header fetching in SubscriptionInfoManager
- Fix units (B/KB/MB/GB/TB)
- Reduce spacing in progress layout
- Thread-safe map updates + snapshot save
Refs: 2dust/v2rayN#8136