feat(phase4): 全部业务模块迁移到 modules/（结构迁移）

- 21 个模块目录（auth/system/dictionary/configuration/cms/member/region/link/notice/job/log/upload/index）
- 每个模块 router.py（合并模块导出多个 router）/schemas.py/service.py/repository.py/models.py
- routers/v1.py 与 routers/__init__.py 改为直接引用 modules，前缀与权限串原样保留
- core/middleware.py 懒加载指向 modules.system.menu / modules.log；core/redis_client.py 指向 modules.job.scheduler
- apps/views|services|forms 全部改为 re-export 垫片
- 迁移后 grep 守门通过：modules/core 无 apps/extensions 残留引用
- 实测登录、27+ 模块接口、写操作 commit、操作日志落库均正常

Co-Authored-By: Claude <noreply@anthropic.com>

apps/forms/position.py

@@ -1,15 +1,2 @@
-from typing import Optional
-
-from pydantic import BaseModel, Field
-
-# 岗位表单验证
-class PositionForm(BaseModel):
-    id: Optional[int] = Field(None, description="岗位ID")
-    name: str = Field(..., min_length=1, max_length=150, description="岗位名称")
-    status: int = Field(..., ge=1, le=2, description="岗位状态")
-    sort: int = Field(..., ge=0, le=99999, description="岗位排序")
-
-# 设置状态表单
-class PositionStatusForm(BaseModel):
-    id: int = Field(..., gt=0, description="岗位ID")
-    status: int = Field(..., ge=1, le=2, description="岗位状态")
+# 兼容垫片：由 modules.system.position.schemas 迁移
+from modules.system.position.schemas import *  # noqa: F401,F403