Summary

• Quitting the app while an editor window is in full screen now correctly restores full screen on next launch.
• Previously, AppKit's implicit fullscreen-exit during app termination fired didExitFullScreenNotification, which our observer interpreted as the user explicitly leaving full screen and wrote false to the persisted bool.

Why

Reproduces every time after #1083 merged: enter full screen, Cmd+Q, relaunch, connect — window opens at the small pre-fullscreen frame in the top-left, never in full screen.

Root cause: setFrameAutosaveName saves the regular frame (not the fullscreen frame), and our didExitFullScreen observer fired during quit, resetting the persisted full-screen flag to false. So both signals were lost.

How

Two-part fix in WindowStateController:

1. Observe NSApplication.willTerminateNotification. At terminate, set isTerminating = true and snapshot every live binding's current full-screen state (window.styleMask.contains(.fullScreen)) to UserDefaults. This captures the truth at the moment of quit, before AppKit's auto-exit animation runs.
2. The didExitFullScreen observer now checks owner.isTerminating and skips the false write during termination. Real user-initiated exits (green button, Esc) still update the bool correctly.

Test plan

• Launch the app, connect to a database, enter full screen, Cmd+Q. Relaunch and connect: window opens in full screen.
• Same flow but exit full screen with the green button before quitting. Relaunch: window opens at the regular pre-fullscreen frame.
• First launch ever (no prior state): window opens at the first-run computed size, not full screen.
• Open multiple connection windows in a tab group, enter full screen on the group, Cmd+Q. Relaunch: tab group opens in full screen.