✨ feat(vscode): 代码阅读预览界面

Vite 加 code-reader.html 第二入口；代码块树（层级竖线、折叠、种类标签配色）、译文 / 源码按词性着色、块内直接编辑（防抖回写整行、Esc 回预览）、翻译下拉、解析失败提示；看板与代码阅读共用带类型的 acquireVsCodeApi 包装和 ErrorBoundary。

vscode/webview-ui/src/codeReader/segments.test.ts

@@ -0,0 +1,67 @@
+import type { Segment } from './types'
+import { describe, expect, it } from 'vitest'
+import { recolor, sliceSegments } from './segments'
+
+const tokens: Segment[] = [
+  { text: 'const', role: 'storage' },
+  { text: ' ', role: 'plain' },
+  { text: 'uris', role: 'variable' },
+  { text: ' = ', role: 'plain' },
+  { text: '42', role: 'number' },
+]
+const code = 'const uris = 42'
+
+function join(segments: Segment[]): string {
+  return segments.map(s => s.text).join('')
+}
+
+describe('sliceSegments', () => {
+  it('跨段切出一段时每个字保留原词性', () => {
+    expect(sliceSegments(tokens, 3, 8)).toEqual([
+      { text: 'st', role: 'storage' },
+      { text: ' ', role: 'plain' },
+      { text: 'ur', role: 'variable' },
+    ])
+  })
+
+  it('空区间返回空数组', () => {
+    expect(sliceSegments(tokens, 4, 4)).toEqual([])
+  })
+})
+
+describe('recolor', () => {
+  it('文字没变时原样返回着色', () => {
+    expect(recolor(tokens, code, code)).toBe(tokens)
+  })
+
+  it('中间插入的字不着色，前后沿用原词性', () => {
+    const text = 'const allUris = 42'
+    const result = recolor(tokens, code, text)
+    expect(join(result)).toBe(text)
+    expect(result).toEqual([
+      { text: 'const', role: 'storage' },
+      { text: ' ', role: 'plain' },
+      { text: 'allU', role: 'plain' },
+      { text: 'ris', role: 'variable' },
+      { text: ' = ', role: 'plain' },
+      { text: '42', role: 'number' },
+    ])
+  })
+
+  it('删掉结尾时只剩前缀的着色', () => {
+    expect(recolor(tokens, code, 'const ur')).toEqual([
+      { text: 'const', role: 'storage' },
+      { text: ' ', role: 'plain' },
+      { text: 'ur', role: 'variable' },
+    ])
+  })
+
+  it('重复字符不会让前后缀重叠', () => {
+    const result = recolor([{ text: 'aa', role: 'variable' }], 'aa', 'aaa')
+    expect(join(result)).toBe('aaa')
+  })
+
+  it('清空后没有任何段', () => {
+    expect(recolor(tokens, code, '')).toEqual([])
+  })
+})