feat: add YAML validation with check command and auto-validation

Implements comprehensive validation before PPTX conversion to catch errors early. Includes element-level validation (colors, fonts, table consistency) and system-level validation (geometry, resources). Supports standalone check command and automatic validation during conversion.

validators/validator.py

@@ -0,0 +1,160 @@
+"""
+主验证器
+
+协调各子验证器，执行完整的 YAML 文件验证。
+"""
+
+from pathlib import Path
+from loaders.yaml_loader import load_yaml_file, validate_presentation_yaml, YAMLError
+from validators.result import ValidationResult, ValidationIssue
+from validators.geometry import GeometryValidator
+from validators.resource import ResourceValidator
+from core.elements import create_element
+
+
+class Validator:
+    """主验证器"""
+
+    # 幻灯片尺寸映射（英寸）
+    SLIDE_SIZES = {
+        "16:9": (10, 5.625),
+        "4:3": (10, 7.5),
+    }
+
+    def __init__(self):
+        """初始化验证器"""
+        pass
+
+    def validate(self, yaml_path: Path, template_dir: Path = None) -> ValidationResult:
+        """
+        验证 YAML 文件
+
+        Args:
+            yaml_path: YAML 文件路径
+            template_dir: 模板文件目录（可选）
+
+        Returns:
+            验证结果
+        """
+        errors = []
+        warnings = []
+        infos = []
+
+        # 1. 加载 YAML
+        try:
+            data = load_yaml_file(yaml_path)
+            validate_presentation_yaml(data, str(yaml_path))
+        except YAMLError as e:
+            errors.append(ValidationIssue(
+                level="ERROR",
+                message=str(e),
+                location="",
+                code="YAML_ERROR"
+            ))
+            return ValidationResult(
+                valid=False,
+                errors=errors,
+                warnings=warnings,
+                infos=infos
+            )
+        except Exception as e:
+            errors.append(ValidationIssue(
+                level="ERROR",
+                message=f"加载 YAML 文件失败: {str(e)}",
+                location="",
+                code="YAML_LOAD_ERROR"
+            ))
+            return ValidationResult(
+                valid=False,
+                errors=errors,
+                warnings=warnings,
+                infos=infos
+            )
+
+        # 获取幻灯片尺寸
+        size_str = data.get('metadata', {}).get('size', '16:9')
+        slide_width, slide_height = self.SLIDE_SIZES.get(size_str, (10, 5.625))
+
+        # 初始化子验证器
+        geometry_validator = GeometryValidator(slide_width, slide_height)
+        resource_validator = ResourceValidator(
+            yaml_dir=yaml_path.parent,
+            template_dir=template_dir
+        )
+
+        # 2. 验证每个幻灯片
+        slides = data.get('slides', [])
+        for slide_index, slide_data in enumerate(slides, start=1):
+            # 验证模板
+            template_issues = resource_validator.validate_template(slide_data, slide_index)
+            self._categorize_issues(template_issues, errors, warnings, infos)
+
+            # 验证元素
+            elements = slide_data.get('elements', [])
+            for elem_index, elem_dict in enumerate(elements, start=1):
+                # 3. 元素级验证
+                try:
+                    element = create_element(elem_dict)
+
+                    # 调用元素的 validate() 方法
+                    if hasattr(element, 'validate'):
+                        elem_issues = element.validate()
+                        # 填充位置信息
+                        for issue in elem_issues:
+                            issue.location = f"幻灯片 {slide_index}, 元素 {elem_index}"
+                        self._categorize_issues(elem_issues, errors, warnings, infos)
+
+                    # 4. 几何验证
+                    geom_issues = geometry_validator.validate_element(
+                        element, slide_index, elem_index
+                    )
+                    self._categorize_issues(geom_issues, errors, warnings, infos)
+
+                    # 5. 资源验证（图片）
+                    if elem_dict.get('type') == 'image':
+                        img_issues = resource_validator.validate_image(
+                            element, slide_index, elem_index
+                        )
+                        self._categorize_issues(img_issues, errors, warnings, infos)
+
+                except ValueError as e:
+                    # 元素创建失败（__post_init__ 中的验证）
+                    errors.append(ValidationIssue(
+                        level="ERROR",
+                        message=str(e),
+                        location=f"幻灯片 {slide_index}, 元素 {elem_index}",
+                        code="ELEMENT_VALIDATION_ERROR"
+                    ))
+                except Exception as e:
+                    errors.append(ValidationIssue(
+                        level="ERROR",
+                        message=f"验证元素时出错: {str(e)}",
+                        location=f"幻灯片 {slide_index}, 元素 {elem_index}",
+                        code="ELEMENT_VALIDATION_ERROR"
+                    ))
+
+        # 返回验证结果
+        return ValidationResult(
+            valid=len(errors) == 0,
+            errors=errors,
+            warnings=warnings,
+            infos=infos
+        )
+
+    def _categorize_issues(self, issues: list, errors: list, warnings: list, infos: list):
+        """
+        将问题按级别分类
+
+        Args:
+            issues: 问题列表
+            errors: 错误列表
+            warnings: 警告列表
+            infos: 提示列表
+        """
+        for issue in issues:
+            if issue.level == "ERROR":
+                errors.append(issue)
+            elif issue.level == "WARNING":
+                warnings.append(issue)
+            elif issue.level == "INFO":
+                infos.append(issue)