fix(sub): omit non-standard fm param from Hysteria2 URI (#6048)

Hysteria2 subscription links included a v2rayN-specific fm=<json>
finalmask dump alongside standard obfs/obfs-password. Clients such as
mihomo reject the unknown query param and fail to update the provider.

Emit only the standard salamander fields in genHysteriaLink, matching
the Clash generator.

Fixes #5982

internal/sub/service.go

@@ -1025,11 +1025,10 @@ func (s *SubService) genHysteriaLink(inbound *model.Inbound, email string) strin
 		}
 	}
 
-	// salamander obfs (Hysteria2). The panel-side link generator already
-	// emits these; keep the subscription output in sync so a client has
-	// the obfs password to match the server.
+	// salamander obfs (Hysteria2). Emit only the standard URI fields;
+	// the non-standard fm=<json> finalmask dump breaks mihomo and other
+	// Hysteria2 clients that reject unknown query params.
 	if finalmask, ok := stream["finalmask"].(map[string]any); ok {
-		applyFinalMaskParams(finalmask, params)
 		if udpMasks, ok := finalmask["udp"].([]any); ok {
 			for _, m := range udpMasks {
 				mask, _ := m.(map[string]any)