fix(bun): support extra generated model fields

pkg/writers/bun/writer.go

@@ -51,6 +51,43 @@ func (w *Writer) WriteDatabase(db *models.Database) error {
 	return w.writeSingleFile(db)
 }
 
+// addExtraFields appends user-defined extra fields to matching models.
+// Fields may be scoped by target_table (table name, schema.table name, or model name).
+// Unscoped fields apply to every generated model.
+func (w *Writer) addExtraFields(templateData *TemplateData) {
+	extraFields := LoadExtraFieldsFromMetadata(w.options.Metadata)
+	if len(extraFields) == 0 {
+		return
+	}
+
+	for _, model := range templateData.Models {
+		for _, ef := range extraFields {
+			if !extraFieldMatchesModel(ef, model) {
+				continue
+			}
+
+			fieldData := &FieldData{
+				Name:    resolveFieldNameCollision(ef.Name),
+				Type:    ef.Type,
+				BunTag:  ef.BunTag,
+				JSONTag: ef.JSONTag,
+				Comment: ef.Comment,
+			}
+			model.ExtraFields = append(model.ExtraFields, fieldData)
+		}
+	}
+}
+
+func extraFieldMatchesModel(field ExtraFieldConfig, model *ModelData) bool {
+	if field.TargetTable == "" {
+		return true
+	}
+
+	return field.TargetTable == model.TableNameOnly ||
+		field.TargetTable == model.TableName ||
+		field.TargetTable == model.Name
+}
+
 // WriteSchema writes a schema as Bun models
 func (w *Writer) WriteSchema(schema *models.Schema) error {
 	// Create a temporary database with just this schema
@@ -107,6 +144,9 @@ func (w *Writer) writeSingleFile(db *models.Database) error {
 		templateData.AddImport("\"fmt\"")
 	}
 
+	// Apply extra fields from generator config (issue #4)
+	w.addExtraFields(templateData)
+
 	// Finalize imports
 	templateData.FinalizeImports()
 
@@ -200,6 +240,9 @@ func (w *Writer) writeMultiFile(db *models.Database) error {
 				templateData.AddImport("\"fmt\"")
 			}
 
+			// Apply extra fields from generator config (issue #4)
+			w.addExtraFields(templateData)
+
 			// Finalize imports
 			templateData.FinalizeImports()