docs: add dialog keyboard shortcuts and selective printing tips

[totally-not-ai]

Summary

This PR adds two docs tips. A new Dialog recipes page shows how to use keyboard shortcuts in a dialog. The Browser Access page now shows how to print only part of the page.

What changed

This is a docs-only change. It does not change any code or how anything behaves.

• New page articles/components/dialog/recipes.adoc (Flow):
  • Escape closes modal dialogs. You can turn this off with setCloseOnEsc(false).
  • To make Enter submit the dialog, add a click shortcut to the main button and limit it to the dialog: addClickShortcut(Key.ENTER).listenOn(dialog).
  • When a footer button has focus, Enter should only press that button. A shortcut listener stops the key event there, and allowBrowserDefault() keeps the button's normal Enter behavior.
  • Links to the "Add Keyboard Shortcuts" guide.
  • It follows the same layout as the Tree Grid recipes page.
• articles/flow/advanced/browser-access.adoc: adds a CSS @media print example. It hides the whole page except the element with the printable class, so only that part is printed.

[github-actions]

Preview Deployment

This PR has been deployed for preview.

URL: https://docs-preview-pr-6236.fly.dev

Changed pages

Added content is highlighted in green; removed content is marked in red on each page.

• components/dialog/recipes — added, +31/-0 lines
• flow/advanced/browser-access — modified, +21/-0 lines

Built from 30398ca

[sissbruecker]

@totally-not-ai Move the dialog keyboard shortcuts example into a "Recipes" sub-page, following the one that TreeGrid already has.

[totally-not-ai]

@sissbruecker Done. The keyboard shortcuts example is now on a new Dialog Recipes sub-page (articles/components/dialog/recipes.adoc), set up the same way as the Tree Grid recipes page (same front matter structure, order: 60 after Styling, Flow badge on the section). I removed it from the Add Dialogs & Popovers guide, which is now unchanged by this PR. The selective printing snippet in Browser Access is unchanged.

[vaadin-bot]

Hi @totally-not-ai[bot] and @sissbruecker, when i performed cherry-pick to this commit to v25.3, i have encountered the following issue. Can you take a look and pick it manually?
Error Message:
Error: Command failed: git cherry-pick 6176ae4
error: could not apply 6176ae4... docs: add dialog keyboard shortcuts and selective printing tips (#6236)
hint: After resolving the conflicts, mark them with
hint: "git add/rm ", then run
hint: "git cherry-pick --continue".
hint: You can instead skip this commit with "git cherry-pick --skip".
hint: To abort and get back to the state before "git cherry-pick",
hint: run "git cherry-pick --abort".