Add a Settings toggle to keep window size when moving a maximized window to another display

[kmundnic]

Summary

Moving a maximized window to the next/previous display currently re-maximizes it to fill the destination display. This is already toggleable via the hidden autoMaximize default, but there's no UI for it, so most users don't know it exists.

This PR exposes it as a "Maximize window when moved to another display" checkbox in Settings, checked by default so existing behavior is unchanged. Unchecking it keeps the window's size and centers it on the destination display — preferable when displays differ in size (e.g. a window maximized on a laptop screen shouldn't grow to fill a larger external monitor). This restores the behavior Spectacle had.

Changes

• SettingsViewController: add the checkbox + description, mirroring the existing greenButtonOverride / combinedDisplayMode programmatic checkboxes (property, toggle action, initializer, config-import refresh).
• Main.xcstrings: register the two new strings.
• TerminalCommands.md: document the autoMaximize default.

Testing

Built and ran locally on a dual-monitor setup:

• Unchecked: a window maximized on the smaller display keeps its size and centers when moved to the larger display.
• Checked (default): the window re-maximizes to fill the larger display, as before.

[rxhanson]

Thanks for contributing! Although this was purposefully left out of the UI to avoid having too many toggles, my plan is to rework some of the UI to allow a lot more things to go in to a different location. I'm ok moving forward with merging this in when I get a chance to review it, with the notion that I will move it to the new location when I have it ready.

[kmundnic]

Thanks! That makes sense. I've just been missing this feature since I moved from Spectacle to Rectangle. No worries about moving it to the new settings section whenever that's ready. I've marked this ready for review.

I've also tested it myself on a dual-monitor setup: with the toggle off, a window maximized on the smaller display keeps its size and centers on the larger one; with it on, it re-maximizes as before. I've attached an image of the UI with the new toggle.

Let me know if you have questions or concerns!