feat(sub): allow identity tokens on every subscription link (#5935)

Keep usage tokens first-link-only while adding an opt-in setting for repeating EMAIL and USERNAME in subscription-body remarks.

Co-authored-by: x06579 <x06579@ai-dashboard>

frontend/src/models/setting.ts

@@ -14,6 +14,7 @@ export class AllSetting {
   expireDiff = 0;
   trafficDiff = 0;
   remarkTemplate = '{{INBOUND}}-{{EMAIL}}|📊{{TRAFFIC_LEFT}}|⏳{{DAYS_LEFT}}D';
+  subShowIdentityOnAllLinks = false;
   datepicker: 'gregorian' | 'jalalian' = 'gregorian';
   tgBotEnable = false;
   tgBotToken = '';