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/binding_handler.go

@@ -157,4 +157,3 @@ func (h *Handler) UpdateBinding(c *gin.Context) {
 
 	c.JSON(http.StatusOK, existing)
 }
-

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)
 	}
 

internal/dto/binding.go

@@ -10,4 +10,3 @@ type BindingDTO struct {
 	SelectorValue string `json:"selector_value"`
 	Status        string `json:"status"`
 }
-