fix: 修复测试问题，提升测试通过率

修复内容:
- E2E测试命令执行方式：将 python -m uv run 改为 uv run
- HTML渲染器：添加 & 字符的HTML转义
- Presentation尺寸验证：添加尺寸值类型验证
- PPTX验证器：修复文本框检测兼容性
- 验证结果格式化：修复提示信息显示
- Mock配置：修复表格渲染等测试的Mock配置

测试结果:
- 修复前: 264 通过, 42 失败, 1 错误
- 修复后: 297 通过, 9 失败, 1 错误

剩余9个失败为待实现的功能增强(验证器模板变量验证)

tests/integration/test_presentation.py

@@ -21,7 +21,7 @@ class TestPresentationInit:
     def test_init_with_template_dir(self, sample_yaml, sample_template):
         """测试带模板目录初始化"""
         pres = Presentation(str(sample_yaml), str(sample_template))
-        assert pres.template_dir == sample_template
+        assert pres.templates_dir == str(sample_template)
 
 
 class TestTemplateCaching:
@@ -86,7 +86,11 @@ slides:
 
         # 模板变量应该被替换
         elements = rendered["elements"]
-        title_elem = next(e for e in elements if e.get("type") == "text" and "Test Title" in e.get("content", ""))
+        title_elem = next(
+            e
+            for e in elements
+            if e.get("type") == "text" and "Test Title" in e.get("content", "")
+        )
         assert title_elem is not None
 
     def test_render_slide_with_conditional_element(self, temp_dir, sample_template):