This fixes two overlapping issues regarding window positioning and Cmd+W window closures on macOS:
1. `window-position-x` and `window-position-y` coordinates were being ignored on initial launch because `TerminalWindow.setInitialWindowPosition` depended on the `TerminalController`, which isn't fully attached during `awakeFromNib`. This logic was moved so explicit coordinates are correctly enforced.
2. When closing a window via Cmd+W (leaving the app active), reopening the window would continuously cascade down and to the right rather than restoring to the previous position. It now checks if there are other windows open before cascading.
3. `LastWindowPosition` was updated to save both the frame origin and size (width/height), ensuring that restoring a closed window correctly mimics native AppKit State Restoration size behaviors while honoring explicit configurations.
