feat(packages/ui): support inline code in sidebar titles #95

Summary

Allow backtick-delimited inline code in sidebar titles, such as `Config` object or `foobar()` function.

Current behavior

Sidebar titles are resolved and serialized as plain strings, so code-like identifiers cannot use the same inline-code treatment as document content.

Proposed scope

• Treat backticks in title strings as inline-code delimiters.
• Preserve the plain string through config and sync; parse it only in the UI renderer.
• Apply the behavior to sidebar labels first. Navbar support is out of scope unless it already shares the same renderer.
• Render text safely without accepting arbitrary HTML.

Acceptance criteria

• Mixed text/code titles render the delimited segment with code styling.
• Titles without backticks are unchanged.
• Escaped or unmatched backticks degrade to readable text.
• Tooltips and accessible names expose the complete plain-text title.
• Tests cover plain, mixed, escaped, and malformed input.