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>

internal/sub/service.go

@@ -40,9 +40,10 @@ type SubService struct {
 	// usageShown tracks, per client email, whether the info part of the template
 	// has already been emitted this request, so it appears on the first body
 	// link only. Per-request state; reset in PrepareForRequest.
-	usageShown     map[string]bool
-	inboundService service.InboundService
-	settingService service.SettingService
+	usageShown             map[string]bool
+	showIdentityOnAllLinks bool
+	inboundService         service.InboundService
+	settingService         service.SettingService
 	// nodesByID is populated per request from the Node table so
 	// resolveInboundAddress can return the node's address for any
 	// inbound whose NodeID is set. Keeps the per-link host derivation
@@ -197,6 +198,10 @@ func (s *SubService) loadRemarkSettings() {
 	if err != nil {
 		s.datepicker = "gregorian"
 	}
+	s.showIdentityOnAllLinks, err = s.settingService.GetSubShowIdentityOnAllLinks()
+	if err != nil {
+		s.showIdentityOnAllLinks = false
+	}
 }
 
 func (s *SubService) configuredPublicHost() string {