feat(ui): replace unicode icons with solid-icons

Swap emoji and unicode glyphs for Tabler components so icons inherit
currentColor and font-size and render consistently across platforms.

- add src/components/doc-icons.ts to resolve doc-entry frontmatter icon
  keys to components; frontmatter now stores semantic keys
- replace the align-*.png assets with TbOutlineAlign* icons
- render RevealManager action SVGs as components instead of injected
  innerHTML strings
- carry completion icons via an optional CompletionItem.icon field

src/doc-entries/md-table.md

@@ -1,6 +1,6 @@
 ---
 tag: md-table
-icon: 📊
+icon: table
 title: 表格组件
 ---
 
@@ -38,7 +38,7 @@ B,另一段描述,第二章]{}
 
 ## 随机抽取
 
-当 `roll=true` 时，表格顶部显示 🎲 随机按钮：
+当 `roll=true` 时，表格顶部显示骰子随机按钮：
 - 普通随机：从所有行中均匀随机选取
 - **加权随机**：当 `label` 列全部为整数或整数范围格式（如 `1-3`）时，以 label 值为权重进行加权随机抽取