refactor(代码生成): 简化代码生成模块配置项和模板逻辑

移除不必要的配置字段如作者、模板类型等，优化字段初始化逻辑
重构模板生成逻辑，移除主子表和树表模板支持
优化前端代码生成页面，简化配置步骤和表单验证
更新文档中的代码生成模块说明和快速开始指南

backend/templates/python/schema.py.j2

@@ -25,7 +25,7 @@
 {% for vo_import in vo_import_list %}
 {{ vo_import }}
 {% endfor %}
-from pydantic import BaseModel, ConfigDict, Field
+from pydantic import BaseModel, ConfigDict, Field, field_validator, model_validator
 
 {% if table.sub %}
 from typing import List, Optional
@@ -41,7 +41,9 @@ class {{ class_name }}CreateSchema(BaseModel):
     """
 
     {% for column in columns %}
+    {% if column.column_name not in ['id', 'creator_id', 'created_at', 'updated_at'] %}
     {{ column.column_name }}: Optional[{{ column.python_type }}] = Field(default=None, description='{{ column.column_comment }}')
+    {% endif %}
     {% endfor %}