refactor: P5 DI 注入 + 中间件迁入 src/core

【依赖注入（解决 core→modules 倒置）】
- src/core/permission.py：PermissionProvider 协议 + check_permission
  （不再 import menu 服务，改从 current_app.extensions['permission_provider'] 获取）
- src/core/middleware.py：整合 check_login/check_demo/transaction/op_log/error_handler
  （op_log 写入器 DI：current_app.extensions['operation_log_writer']）
- application/factory.py：组合根注入 MenuPermissionProvider + record_operation_log
- src/core/scheduler.py 懒加载指向 src.modules.job.scheduler_service

【验收】src/core 内零 application 引用；DI 注入验证通过；
未登录 401、白名单放行；12 passed；core+中间件 flake8 零告警

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

src/core/scheduler.py

@@ -87,7 +87,7 @@ class Scheduler:
         # ============================================================
         with app.app_context():
             try:
-                from application.services.scheduler import reload_scheduler
+                from src.modules.job.scheduler_service import reload_scheduler
 
                 # 重新加载所有任务
                 count = reload_scheduler()
@@ -109,7 +109,7 @@ class Scheduler:
     def _log_scheduler_status(self):
         """打印调度器状态（用于调试）"""
         try:
-            from application.services.scheduler import scheduler
+            from src.modules.job.scheduler_service import scheduler
 
             if scheduler.running:
                 jobs = scheduler.get_jobs()
@@ -131,7 +131,7 @@ class Scheduler:
         在应用退出时调用
         """
         try:
-            from application.services.scheduler import scheduler
+            from src.modules.job.scheduler_service import scheduler
 
             if scheduler.running:
                 scheduler.shutdown()
@@ -147,7 +147,7 @@ class Scheduler:
             int: 成功加载的任务数量
         """
         try:
-            from application.services.scheduler import reload_scheduler
+            from src.modules.job.scheduler_service import reload_scheduler
             count = reload_scheduler()
             logger.info(f"重新加载定时任务完成，共加载 {count} 个任务")
             return count
@@ -163,7 +163,7 @@ class Scheduler:
             dict: 包含调度器运行状态和任务列表
         """
         try:
-            from application.services.scheduler import scheduler
+            from src.modules.job.scheduler_service import scheduler
 
             jobs = scheduler.get_jobs()
             job_list = []