fix: 保留文本格式（换行和段落）

[minorcell]

Requested by @minorcell

修复 #70：保存的文本内容现在能正确保留原始格式

问题描述

之前保存的文本内容会丢失格式，多个段落被压缩成一个段落，换行符也消失了。

修复方案

在文本显示组件中添加 CSS 属性 whiteSpace: "pre-wrap"，该属性可以：

• 保留文本中的换行符和空格
• 自动换行以适应容器宽度
• 保持原始文本的段落结构

修改文件

1. src/components/ItemCard.tsx (第194行)

   • 在卡片视图的文本显示中添加 whiteSpace: "pre-wrap"

2. src/components/ShareCard.tsx (第111行)

   • 在分享卡片的文本显示中添加 whiteSpace: "pre-wrap"
   • 确保导出的图片也能正确显示格式

测试建议

1. 保存一段包含多个段落的文本（使用回车键分段）
2. 在列表视图中查看是否保留了段落分隔
3. 点击查看详情，确认完整格式正确
4. 导出为图片，验证图片中的格式也正确

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Generated with codeagent

[minorcell]

Code Review Summary

Overall, this is a well-implemented fix with correct CSS usage. The whiteSpace: "pre-wrap" property appropriately preserves text formatting. No security or performance concerns identified.

Key Finding: Documentation gaps need addressing. The PR description should mention that ItemDialog.tsx already uses this pattern (lines 196, 272), and inline comments would help future maintainers understand why this property is critical for issue #70.

[minorcell]

Consider adding an inline comment explaining why whiteSpace: "pre-wrap" is needed:

sx={{
  // Preserve line breaks and spaces to prevent text collapsing (fixes #70)
  whiteSpace: "pre-wrap",
  lineHeight: 1.9,
  // ...
}}

This helps future maintainers understand the purpose and prevents accidental removal.

[minorcell]

Same as ItemCard.tsx - consider adding a comment:

wordBreak: "break-word",
// Preserve line breaks and spaces (fixes #70)
whiteSpace: "pre-wrap",
fontFamily: "'Noto Serif SC', 'Songti SC', serif"

This ensures the exported share card maintains consistent formatting with the display views.