feat: include page title in list_pages output

[serhiizghama]

Motivation

list_pages shows each page's URL but not its title, which is painful when multiple pages share a host — e.g. several tabs under app.example.com/u/0/, /u/1/, /u/2/. There's no way to tell which is which without visiting each one, even though every page has a usable document.title.

Fixes #2156.

What this changes

• list_pages text output now shows the title before the URL when available: 1: My Page (https://example.com) [selected]. If the page has no title (e.g. about:blank), the format is unchanged.
• The structured content entry for each page now includes a title field alongside id, url, and selected.
• page.title() is awaited with a .catch(() => '') so a closed or erroring page silently falls back to the URL-only format.
• format() is made async to support the await inside the page loop; createStructuredPage() likewise becomes async.

Testing

Start the MCP server with multiple tabs open. Call list_pages — pages with titles now display as id: Title (url). Pages without titles (about:blank, data URLs) display as before.