fix(files): decode markdown refs, scope links to the preview session, drop name= from the sanitizer

Review follow-up on #503. marked percent-encodes link and image destinations, and the rebase pass encoded them a second time, so a space or a CJK character in a file name made file-raw look for a file literally named my%20image.png; refs are now decoded once (a malformed escape is kept as written) and stripped of ?query along with #fragment. Root-relative refs resolve from the workspace root as on GitHub instead of falling through as Codeman URLs. Rebased links carry the preview's own session id and the response-viewer delegate prefers it, so a document opened from another session's attachment card opens its links in that workspace rather than the active tab's.

The sanitizer no longer allows name=: marked never emits it, and <img name="app"> made document.app that image, which every inline onclick="app.…()" handler resolves before the global, so one rendered README broke every viewer button until a reload. Adds the zh-CN strings for the three toolbar titles.

src/web/public/i18n.js

@@ -727,6 +727,9 @@
     'Source type filter': '来源类型筛选',
     'Copy content': '复制内容',
     'Edit file': '编辑文件',
+    'Rendered markdown': '渲染 Markdown',
+    'Line numbers': '行号',
+    'Wrap lines': '自动换行',
     'Unsaved changes': '未保存的更改',
     Saved: '已保存',
     'Export as JSON': '导出为 JSON',