chore: 切换到 bun publish，修复 husky 路径问题，调整 diff 折叠距离，导出 VoiceContext

- publish-npm.yml: npm publish → bun publish，移除 setup-node，使用 BUN_CONFIG_TOKEN
- package.json: prepare 脚本 husky → bunx husky，版本 2.4.4 → 2.4.5
- Messages.tsx: DIFF_COLLAPSE_DISTANCE 从 0 改为 3，避免 diff 过度折叠
- voice.tsx: 导出 VoiceContext

.github/workflows/publish-npm.yml

@@ -24,11 +24,6 @@ jobs:
         with:
           ref: ${{ github.event.inputs.version || github.ref }}
 
-      - uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6, 2026-04-25
-        with:
-          node-version: "24"
-          registry-url: "https://registry.npmjs.org"
-
       - name: Setup Bun
         uses: oven-sh/setup-bun@0c5077e51419868618aeaa5fe8019c62421857d6 # v2, 2026-04-25
         with:
@@ -43,9 +38,9 @@ jobs:
         run: bun test
 
       - name: Publish to npm
-        run: npm publish --provenance --access public
+        run: bun publish --access public
         env:
-          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}
+          BUN_CONFIG_TOKEN: ${{ secrets.NPM_TOKEN }}
 
       - name: Generate changelog
         id: changelog