MarkdownCte: Add option to show actual urls along with anchor text

[tig]

Summary

When printing Markdown, hyperlinks currently render as colored anchor text only — the destination URL is discarded. On paper (and in PDFs shared offline) that loses the useful part of the link. Add a Markdown CTE option to emit the URL alongside (or instead of-only) the anchor text.

Current behavior

In MarkdownCte.FlattenInlines, a LinkInline is flattened to its child text in link color; the Url is never emitted:

case LinkInline link:
    FlattenInlines(link, scale, style, LinkColor, tokens);
    break;
case AutolinkInline auto:
    AppendText(auto.Url, scale, style, LinkColor, tokens);
    break;

So [GitHub Pages](https://pages.github.com/) prints as blue GitHub Pages, while bare autolinks already show the URL.

Settings already live on MarkdownCte (RenderMermaidDiagrams, MermaidBackend, …) and are copied via CopyPropertiesFrom / persisted under markdownContentTypeEngineSettings in WinPrint.config.json.

Proposed behavior

Add a boolean setting (name TBD), e.g. ShowLinkUrls (default false to preserve today’s look):

Markdown	Today	With option on
[GitHub Pages](https://pages.github.com/)	GitHub Pages	GitHub Pages (https://pages.github.com/)
<https://example.com> / autolink	URL (unchanged)	URL (unchanged)
[same as url](https://example.com)	text	Prefer not duplicating if anchor text equals URL

Suggested formatting (open to bikeshed):

• anchor text (url) after the link text, same scale/style, still in link color (or dimmer for the parenthetical).
• Skip when link.Url is empty/null.
• Skip (or don’t double) when normalized anchor text equals the URL.
• Images (link.IsImage) stay out of scope.

Scope

• New property on MarkdownCte + CopyPropertiesFrom
• Persist via existing engine settings path
• Emit URL in the LinkInline flatten path
• Unit test(s) with RecordingGraphicsContext / existing Markdown CTE tests
• Optional: TUI/GUI toggle later; config-only is fine for v1

Why

Print is the product’s job: clickable styling doesn’t help on a physical page or a static PDF. Showing destinations is a common “print-friendly links” feature and matches how many “print stylesheet” / “readable print” tools behave.