Fix native macOS tabs being treated as separate windows

[EdenRochmanSharabi]

Summary

Fixes #68. macOS accessibility API reports native tabs as separate AXWindow elements, causing AeroSpace to tile each tab as its own window (e.g., Terminal with 3 tabs creates 3 tiled windows, 2 of which are empty).

This PR detects inactive native tabs using CGWindowListCopyWindowInfo (public API, no private APIs): if a window detected by the AX API is not on-screen but another window from the same app is on-screen, it's an inactive background tab and should not be tiled.

Changes

• windowLevelCache.swift: Extended the CG window info cache to track bounds and owner PID alongside window level. Added isLikelyNativeTab(windowId:appPid:) function.
• MacWindow.swift: Check isLikelyNativeTab before binding new windows — detected tabs go to the popup container instead of tiling.
• normalizeLayoutReason.swift: Added demoteNativeTabsToPopup() to move tiled windows that become inactive tabs (e.g., after the user opens a new tab) to the popup container. Modified validateStillPopups() to skip promoting windows that are still native tabs.

How it works

1. New window detected: If CGWindowListCopyWindowInfo(.optionOnScreenOnly) doesn't include the window but does include another window from the same PID → it's a background tab → popup container.
2. Tab switch: When the user switches tabs, the previously active tab disappears from the on-screen list → demoteNativeTabsToPopup() moves it to popup. The newly active tab either gets detected as new or gets promoted from popup via validateStillPopups().
3. Tab closed: When the active tab is closed, the next tab becomes on-screen → promoted from popup to tiling automatically.

Tested with

• Terminal.app (multiple tabs, rapid tab creation, tab switching, tab closing)
• Finder (native tabs)
• Safari (native tabs)
• Mixed: multiple apps with tabs simultaneously
• Two separate windows of the same app (correctly tiled, not confused with tabs)
• Moving windows between workspaces (not confused with tabs)

Test plan

• Open Terminal with 3+ tabs → only 1 should be tiled
• Switch between tabs → tiled window updates to active tab
• Close active tab → next tab promotes to tiling
• Open 2 separate Terminal windows → both tile normally
• Open Finder/Safari with tabs → same behavior
• Move window to another workspace → not confused with tabs

[nikitabobko]

The PR is a workaround and not a complete fix. Also please make sure to read all the discussions around this issue

A complete fix is much more complicated and I don't expect 3rd party contributors to fix this issue

[EdenRochmanSharabi]

I am well aware that it is a workaround and not perfect. It introduced a smaller bug: when you navigate between tabs in the same app while you have three apps open vertically, sometimes the order of the apps swaps. However, I think that bug is less frustrating than the current one. I understand it is a workaround, but I thought it was a good temporary solution.