refactor: implement UI code optimization and refactoring

This commit implements the comprehensive UI code refactoring plan to improve
code quality, reduce duplication, and enhance maintainability.

Phase 1: High Priority Improvements
- Create BaseDialog class to eliminate window centering code duplication
  across ProgressDialog, DeleteProgressWindow, LoginDialog, and
  UserSelectionDialog (~30 lines of duplicate code removed)
- Unify log color configuration with LogTheme class in gui/log_config.py
- Create permission check decorators (@require_admin, @require_permission,
  @require_user_type, @handle_errors)
- Update all dialog classes to use unified patterns

Phase 2: Architecture Improvements
- Create input validation framework (ValidationResult, Validator,
  ValidatedWidget classes)
- Implement StateManager with observer pattern for component state sharing
- Create unified ErrorHandler for consistent error handling
- Extract CheckboxTreeview into reusable component

New Modules:
- gui/widgets/base_dialog.py - Base dialog class with modal setup and centering
- gui/utils/decorators.py - Permission and error handling decorators
- gui/utils/error_handler.py - Unified error handling with user-friendly messages
- gui/utils/state_manager.py - State management with observer pattern
- gui/utils/validators.py - Input validation framework
- gui/material_validation/checkbox_treeview.py - Reusable checkbox table

Modified Files:
- gui/log_config.py - Added LogTheme class for centralized styling
- gui/widgets/log_text.py - Use LogTheme.COLORS
- gui/widgets/progress_dialog.py - Inherit from BaseDialog
- gui/widgets/delete_progress_window.py - Inherit from BaseDialog, use LogTheme
- gui/widgets/__init__.py - Add new exports, optional imports
- gui/login_dialog.py - Use unified centering pattern
- gui/user_selection_dialog.py - Use unified centering pattern
- gui/material_validation_tab.py - Import CheckboxTreeview from new module

Benefits:
- Reduced code duplication by ~200 lines
- Improved maintainability through centralized configuration
- Better abstraction with 5 new reusable base classes
- Enhanced type safety with type hints
- Future-proof theming support via LogTheme

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

gui/widgets/base_dialog.py

@@ -0,0 +1,117 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+"""
+Base Dialog - 基础对话框类
+
+所有对话框的基类，提供通用功能：
+- 模态对话框设置
+- 窗口居中显示
+- 统一的对话框生命周期管理
+"""
+import tkinter as tk
+from typing import Optional
+
+
+class BaseDialog(tk.Toplevel):
+    """
+    所有对话框的基类，提供通用功能
+
+    Usage:
+        class MyDialog(BaseDialog):
+            def __init__(self, parent):
+                super().__init__(parent, title="My Dialog")
+                self._create_content()
+
+            def _create_content(self):
+                # 创建对话框内容
+                pass
+
+        dialog = MyDialog(parent)
+        result = dialog.get_result()
+    """
+
+    def __init__(self, parent, title: str, **kwargs):
+        """
+        初始化基础对话框
+
+        Args:
+            parent: 父窗口
+            title: 对话框标题
+            **kwargs: 传递给 tk.Toplevel 的其他参数
+        """
+        super().__init__(parent, **kwargs)
+
+        self.parent = parent
+        self.result = None
+        self.title(title)
+
+        # 设置为模态对话框并居中
+        self._setup_modal()
+
+    def _setup_modal(self):
+        """设置为模态对话框并居中"""
+        self.transient(self.parent)
+        self.grab_set()
+        self._center_window()
+
+    def _center_window(self):
+        """
+        窗口居中显示（统一实现）
+
+        根据对话框大小自动居中到屏幕中央
+        """
+        self.update_idletasks()
+        width = self.winfo_width()
+        height = self.winfo_height()
+
+        # 如果窗口还没有实际大小，使用默认最小值
+        if width <= 1:
+            width = 400
+        if height <= 1:
+            height = 300
+
+        x = (self.winfo_screenwidth() // 2) - (width // 2)
+        y = (self.winfo_screenheight() // 2) - (height // 2)
+        self.geometry(f'{width}x{height}+{x}+{y}')
+
+    def _center_on_parent(self):
+        """
+        窗口居中到父窗口
+
+        将对话框居中显示在父窗口中央，而不是屏幕中央
+        """
+        self.update_idletasks()
+        self.parent.update_idletasks()
+
+        width = self.winfo_width()
+        height = self.winfo_height()
+
+        # 如果窗口还没有实际大小，使用默认最小值
+        if width <= 1:
+            width = 400
+        if height <= 1:
+            height = 300
+
+        parent_x = self.parent.winfo_x()
+        parent_y = self.parent.winfo_y()
+        parent_width = self.parent.winfo_width()
+        parent_height = self.parent.winfo_height()
+
+        x = parent_x + (parent_width - width) // 2
+        y = parent_y + (parent_height - height) // 2
+        self.geometry(f"{width}x{height}+{x}+{y}")
+
+    def get_result(self):
+        """
+        获取对话框结果
+
+        子类应设置 self.result 来返回结果
+
+        Returns:
+            对话框结果，类型由子类定义
+        """
+        return self.result
+
+    def close(self):
+        """关闭对话框"""
+        self.destroy()