Add feature: Split New tab on Right with URL focus using shortcut (As seen on Arc Browser)

[saikanam]

Split New Tab on Right with Keyboard Shortcut

This PR adds a new keyboard shortcut (Ctrl+Shift+'+') that:

• Creates a vertical split view with a new tab on the right
• Automatically focuses the URL bar for immediate navigation
• Allows adding multiple tabs to the right by repeatedly pressing the shortcut

Why This Feature?

This enhances the Split View functionality by providing a quick keyboard-driven workflow for creating and navigating split tabs. It's particularly useful for users who prefer keyboard shortcuts over mouse interactions.

Implementation Details

• Added a new method createSplitNewTabToRight() to ZenViewSplitter.mjs
• Registered the shortcut in ZenKeyboardShortcuts.mjs
• Added support for adding multiple tabs to the right side
• Ensured proper URL bar focus behavior

Localization Strings

This feature requires the following localization string to be added to the appropriate files in the l10n submodule:
zen-split-view-shortcut-url-focus = Split View with URL Focus

Since these files are in a submodule, I've not included them in this PR.

Image demo

[mauro-balades]

Id rather it opens an empty tab instead of about:blank

[saikanam]

Changed it to add newtab instead of blank, thanks.

One thing I forgot to mention is that max split tabs are 4, same as this.MAX_TABS

[mauro-balades]

Sorry, I meant as it opens this empty state:

and please do fix linter errors: https://github.com/zen-browser/desktop/actions/runs/13865573260/job/38942146067?pr=6460

[saikanam]

I fixed the linter errors.
That is strange if it opens the browser in that state, atleast that's what I think you mean.

Let me investigate further on a new build.

[saikanam]

It works as intended on my end, please let me know if I am missing something.

The intent was to open a new split tab to the right which is empty.

That's what happens in Arc as well, when you click control + shift + '+', it opens a new empty tab on the right alongside the url bar.

ArcBrowserSplit.1.mp4

[saikanam]

zenBrowserSplit.mp4

A demo of the intended workflow

[mauro-balades]

Ok, it looks good. But @saikanam could you please always open about:blank and add _forZenEmptyTab to the parameters?

[saikanam]

If I add _forZenEmptyTab in the parameters,it breaks the functionality by unsplitting the tabs. This is most likely due to this attribute being heavily used in other parts of zenViewSplitter to make certain filtration.

Is this attribute absolutely necessary to add? I might have to find a workaround then.