style(core): align struct tags and fields

Standardize alignment of struct tags in models and field assignments in
services for better readability. Additionally, include the Binding model
in the test database auto-migration.

internal/api/provider_handler_test.go

@@ -28,7 +28,7 @@ func newTestHandler(t *testing.T) (*Handler, *gorm.DB) {
 	if err != nil {
 		t.Fatalf("open sqlite: %v", err)
 	}
-	if err := db.AutoMigrate(&model.Provider{}); err != nil {
+	if err := db.AutoMigrate(&model.Provider{}, &model.Binding{}); err != nil {
 		t.Fatalf("migrate: %v", err)
 	}