Add twelfths (3x4) and sixteenths (4x4) grid positions

[MyronKoch]

Summary

• Adds 12 twelfths (3 columns x 4 rows) and 16 sixteenths (4 columns x 4 rows) window positions
• Each position includes a calculation class with OrientationAware support and bidirectional cycling via TwelfthsRepeated/SixteenthsRepeated protocols
• Includes pixel-accurate 30x20px template image assets matching the existing icon style
• Adds .twelfths and .sixteenths categories to WindowActionCategory

Motivation

These finer grid positions are especially useful for users with large or ultra-high-resolution displays - 50" 4K TVs used as monitors, ultrawide displays, or multi-monitor arrays - where halves, thirds, and quarters leave too much unused screen real estate. A 4x4 grid on a 50" 4K display gives each tile roughly the usable area of a 720p laptop screen, which is ideal for tiling many windows simultaneously.

Changes

• WindowAction.swift - 28 new enum cases (raw values 80-119), with name, displayName, image, category, gapsApplicable, alternateDefault, SubWindowAction, and gapSharedEdge entries
• WindowActionCategory.swift - .twelfths and .sixteenths cases
• WindowCalculation.swift - 28 factory instances and calculationsByAction entries
• 28 new *Calculation.swift files (one per position)
• TwelfthsRepeated.swift and SixteenthsRepeated.swift - cycling protocols
• 28 image assets in Assets.xcassets/WindowPositions/
• PrefsViewController.swift - shortcut views for twelfths and sixteenths categories
• project.pbxproj - build file references for all new files

Test plan

• Build succeeds with no warnings in the new files
• Each twelfth position tiles correctly on a standard display
• Each sixteenth position tiles correctly on a standard display
• Cycling through twelfths and sixteenths works in both directions
• Gap settings apply correctly to all new positions (shared edges respected)
• OrientationAware behavior swaps correctly in portrait mode
• Menu items appear under new Twelfths and Sixteenths submenus
• Template images render correctly in light and dark mode

🤖 Generated with Claude Code

[rxhanson]

Thanks for looking to contribute to Rectangle.

Rectangle's Shortcuts tab is a bit limited by design, as the intent is to keep the app more approachable. More recently I've designated the "overflow" area for new sizes/positions to the popover shown by the ellipsis button on at the bottom of the General tab. That provides a middle ground where the simple aesthetic is preserved but the community has the ability to add more to the app as desired.

I'm good with merging in more sizes/positions, but when added to the UI it has to still be done in a way that is visually acceptable in the popover. In this case, some options would be adding in more columns or converting the existing settings in that popover into a table view that can scroll.

If that's not desirable, another option is to leave all of the additions out of the UI and keep them as Terminal command configurations only at this time.

Let me know if you have any questions.

[MyronKoch]

Thanks for the guidance on the popover pattern! I've moved the twelfths and sixteenths shortcuts into the ellipsis popover on the General tab using a cycling approach: one shortcut per grid size that cycles through all positions on repeated presses (using the existing *Repeated protocols). This adds just 3 compact rows instead of 28 individual ones.

Here's how it looks in the popover - note the "Grid Positions" section at the bottom with the cycling hint:

I'll update the PR branch to reflect this. The ninths (3x3) are also included as a cycling shortcut since they were already fully implemented but only individually configurable.

Let me know if this direction works for the popover UI.

[rxhanson]

Thanks for the update. I pulled your changes, and now looking at this cohesively as this one pull request I have clarity on criteria for getting this into a mergeable state:

• We can remove the "use cycling shortcuts" checkbox and simply leave the Ninths, Twelfths, and Sixteenths as the single Shortcut recorder. For these it is less likely that individual shortcut recorders would be beneficial enough to justify adding them in, and then we don't have to worry about showing/hiding in the popover and readjusting it's size accordingly.
• Instead of the "Show Eighths in Menu" Checkbox, let's have a single checkbox that adds all of the additional menus with submenus (8ths, 12ths, 16ths, and 9ths if desired), and converts the Thirds & Size menu items into submenus as proposed in the other PR.

I think this gives us the benefit of the additional sizes with a reasonable menu, without adding too much complexity to the popover, and it preserves the existing simplicity for users that don't have large screens.

Let me know if anything's unclear here.

[MyronKoch]

Thanks for the clear guidance - this is much cleaner.

Changes made:

Popover (General tab > ellipsis):

• Removed the "Use cycling shortcuts" checkbox and all 28 individual twelfths/sixteenths rows
• Now shows just 3 cycling shortcut recorders: Ninths (3x3), Twelfths (4x3), Sixteenths (4x4)
• Kept the cycling hint text explaining "press repeatedly to cycle"

Menu checkbox:

• Replaced "Show Eighths in Menu" with "Show additional sizes in menu"
• When enabled: shows Eighths, Ninths, Twelfths, and Sixteenths submenus, and converts Thirds & Size into submenus
• When disabled (default): hides those submenus, preserving the existing simple menu

Cleanup:

• Merged the menu submenus PR (Organize thirds and size actions into menu submenus #1721) into this one since it's now a single cohesive feature
• Added Ninths as a menu category
• Removed useCyclingShortcuts preference (no longer needed)
• Net -454 lines

If this looks right I can close #1721 since its changes are incorporated here.