chore(test): clean up unused code and fix test helper usage

- Update TestBatchBindings_Status to use newTestHandlerWithRedis helper
- Remove unused jsonID helper function from sync_bindings_spec_test.go
- Add time import to models.go

internal/model/models.go

@@ -1,6 +1,10 @@
 package model
 
-import "gorm.io/gorm"
+import (
+	"time"
+
+	"gorm.io/gorm"
+)
 
 // Admin is not a database model. It's configured via environment variables.