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.

core/elements.py

@@ -5,7 +5,22 @@
 """
 
 from dataclasses import dataclass, field
-from typing import Optional
+from typing import Optional, List
+import re
+
+
+def _is_valid_color(color: str) -> bool:
+    """
+    验证颜色格式是否正确
+
+    Args:
+        color: 颜色字符串
+
+    Returns:
+        是否为有效的颜色格式（#RGB 或 #RRGGBB）
+    """
+    pattern = r'^#([0-9A-Fa-f]{3}|[0-9A-Fa-f]{6})$'
+    return bool(re.match(pattern, color))
 
 
 @dataclass
@@ -21,6 +36,41 @@ class TextElement:
         if not isinstance(self.box, list) or len(self.box) != 4:
             raise ValueError("box 必须是包含 4 个数字的列表")
 
+    def validate(self) -> List:
+        """验证元素自身的完整性"""
+        from validators.result import ValidationIssue
+        issues = []
+
+        # 检查颜色格式
+        if self.font.get('color'):
+            if not _is_valid_color(self.font['color']):
+                issues.append(ValidationIssue(
+                    level="ERROR",
+                    message=f"无效的颜色格式: {self.font['color']} (应为 #RRGGBB)",
+                    location="",
+                    code="INVALID_COLOR_FORMAT"
+                ))
+
+        # 检查字体大小
+        if self.font.get('size'):
+            size = self.font['size']
+            if size < 8:
+                issues.append(ValidationIssue(
+                    level="WARNING",
+                    message=f"字体太小: {size}pt (建议 >= 8pt)",
+                    location="",
+                    code="FONT_TOO_SMALL"
+                ))
+            elif size > 100:
+                issues.append(ValidationIssue(
+                    level="WARNING",
+                    message=f"字体太大: {size}pt (建议 <= 100pt)",
+                    location="",
+                    code="FONT_TOO_LARGE"
+                ))
+
+        return issues
+
 
 @dataclass
 class ImageElement:
@@ -36,6 +86,12 @@ class ImageElement:
         if not isinstance(self.box, list) or len(self.box) != 4:
             raise ValueError("box 必须是包含 4 个数字的列表")
 
+    def validate(self) -> List:
+        """验证元素自身的完整性"""
+        # ImageElement 的必需字段已在 __post_init__ 中检查
+        # 这里返回空列表，资源验证由 ResourceValidator 负责
+        return []
+
 
 @dataclass
 class ShapeElement:
@@ -51,6 +107,42 @@ class ShapeElement:
         if not isinstance(self.box, list) or len(self.box) != 4:
             raise ValueError("box 必须是包含 4 个数字的列表")
 
+    def validate(self) -> List:
+        """验证元素自身的完整性"""
+        from validators.result import ValidationIssue
+        issues = []
+
+        # 检查形状类型枚举
+        valid_shapes = ['rectangle', 'ellipse', 'rounded_rectangle']
+        if self.shape not in valid_shapes:
+            issues.append(ValidationIssue(
+                level="ERROR",
+                message=f"不支持的形状类型: {self.shape} (支持: {', '.join(valid_shapes)})",
+                location="",
+                code="INVALID_SHAPE_TYPE"
+            ))
+
+        # 检查填充颜色格式
+        if self.fill and not _is_valid_color(self.fill):
+            issues.append(ValidationIssue(
+                level="ERROR",
+                message=f"无效的填充颜色格式: {self.fill} (应为 #RRGGBB)",
+                location="",
+                code="INVALID_COLOR_FORMAT"
+            ))
+
+        # 检查线条颜色格式
+        if self.line and self.line.get('color'):
+            if not _is_valid_color(self.line['color']):
+                issues.append(ValidationIssue(
+                    level="ERROR",
+                    message=f"无效的线条颜色格式: {self.line['color']} (应为 #RRGGBB)",
+                    location="",
+                    code="INVALID_COLOR_FORMAT"
+                ))
+
+        return issues
+
 
 @dataclass
 class TableElement:
@@ -68,6 +160,37 @@ class TableElement:
         if not isinstance(self.position, list) or len(self.position) != 2:
             raise ValueError("position 必须是包含 2 个数字的列表")
 
+    def validate(self) -> List:
+        """验证元素自身的完整性"""
+        from validators.result import ValidationIssue
+        issues = []
+
+        # 检查表格数据行列数一致性
+        if self.data:
+            first_row_cols = len(self.data[0]) if isinstance(self.data[0], list) else 0
+            for i, row in enumerate(self.data[1:], start=1):
+                if isinstance(row, list):
+                    if len(row) != first_row_cols:
+                        issues.append(ValidationIssue(
+                            level="ERROR",
+                            message=f"表格数据行列数不一致: 第 {i+1} 行有 {len(row)} 列，期望 {first_row_cols} 列",
+                            location="",
+                            code="TABLE_INCONSISTENT_COLUMNS"
+                        ))
+
+        # 检查 col_widths 与列数是否匹配
+        if self.col_widths and self.data:
+            first_row_cols = len(self.data[0]) if isinstance(self.data[0], list) else 0
+            if len(self.col_widths) != first_row_cols:
+                issues.append(ValidationIssue(
+                    level="WARNING",
+                    message=f"col_widths 数量 ({len(self.col_widths)}) 与表格列数 ({first_row_cols}) 不匹配",
+                    location="",
+                    code="TABLE_COL_WIDTHS_MISMATCH"
+                ))
+
+        return issues
+
 
 def create_element(elem_dict: dict):
     """