T-8: Enable NSWindow.allowsAutomaticWindowTabbing

[kirich1409]

Part of EPIC #193. Depends on #201.

Description

Set NSWindow.allowsAutomaticWindowTabbing = true in AppDelegate.applicationDidFinishLaunching. macOS will then group project windows into system tabs when the user has "Prefer tabs when opening documents" enabled in System Settings.

Acceptance Criteria

• With System Settings → Desktop & Dock → "Prefer tabs when opening documents" set to "Always", new project windows are grouped into system tabs
• Window menu shows "Merge All Windows" and "Move Tab to New Window"
• With the setting at "Never", each project window is a separate window (current behaviour)

Module / Layer

Relay / AppDelegate

Complexity

Small