feat: implement user authentication and permission-based data filtering

Add user login system with role-based access control:
- Admin users see all data and can filter by any manager
- Regular users only see records where ManagerName matches their username

New components:
- BIPUsersDAO: user authentication and management
- SessionManager: singleton session state management
- LoginDialog: modal login UI for app startup
- init_users.sql: initial user setup script

Permission enforcement:
- Material validation tab: hide manager filter for non-admin, force filter by current user
- Material type management: hide filter UI for non-admin, filter at database level
- Window title and status bar display current user info

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

main_ui.py

@@ -14,10 +14,14 @@ ERP 自动化工具 - GUI 版本
     - 物料校验：校验物料状态并匹配待删除物料
     - 数据查询：查询生产订单号等信息
     - 设置管理：管理系统配置
+    - 用户认证：基于用户权限的数据访问控制
 """
 
 import tkinter as tk
+from tkinter import messagebox
 from gui.main_window import MainWindow
+from gui.login_dialog import LoginDialog
+from auth.session_manager import SessionManager
 
 
 def main():
@@ -25,8 +29,27 @@ def main():
     # 创建根窗口
     root = tk.Tk()
 
-    # 创建主窗口
-    app = MainWindow(root)
+    # 显示登录对话框
+    login_dialog = LoginDialog(root)
+    credentials = login_dialog.get_credentials()
+
+    if not credentials:
+        # 用户取消登录或关闭对话框
+        root.destroy()
+        return
+
+    username, password = credentials
+
+    # 认证并初始化会话
+    session_manager = SessionManager.get_instance()
+
+    if not session_manager.login(username, password):
+        messagebox.showerror("登录失败", "用户名或密码错误")
+        root.destroy()
+        return
+
+    # 创建主窗口（传入 session_manager）
+    app = MainWindow(root, session_manager)
 
     # 启动主事件循环
     root.mainloop()