* fix(web): show the localized label for untitled notes everywhere
Untitled notes are stored with the zh-CN default title, and several views
only replaced an empty title, so they showed 无标题笔记 in every locale.
The visible cases were the public share page (heading and browser tab),
the public notebook site, AI companion cards and mentions, the note link
picker, link text inserted for a note, and the title of a duplicated
note.
Add getMemoDisplayTitle() next to DEFAULT_MEMO_TITLE and use it in those
views, matching what MemoCard already does with isDefaultMemoTitle.
* fix(web): localize diagrams and content label on the public share page
The public share page passed zh-CN to read-only diagrams for every
language other than English, so Japanese and Polish visitors saw Chinese
diagram labels. Resolve the locale with resolveSupportedLocale(), which
the diagram renderer already supports for all four languages.
Also translate the note content aria-label, which was hard-coded in
English.
---------
Co-authored-by: tianma-if <yingwaizhiying@gmail.com>
