feat: Claude Sonnet 429 仅限模型限流

backend/internal/service/antigravity_quota_scope.go

@@ -49,6 +49,9 @@ func (a *Account) IsSchedulableForModel(requestedModel string) bool {
 	if !a.IsSchedulable() {
 		return false
 	}
+	if a.isModelRateLimited(requestedModel) {
+		return false
+	}
 	if a.Platform != PlatformAntigravity {
 		return true
 	}