Description

Fixes a few issues with the windowing system, the toolbar, and the inspector.

• Makes the activity view resizable
• Removes the jank code used for the inspector tracking item in the toolbar
  • Replaces it with an inspector split item, allowing AppKit to handle the tracking exactly like Xcode's.
  • Removes animation glitches made more obvious with the activity view.
  • This also fixes a small bug where the inspector tracking item would be visible when the app opened and the inspector was closed.
• Removes the root SwiftUI view, which was causing a lot of layout issues with the toolbar & inspector toggling. SwiftUI doesn't interop well with this stuff, so if in the future we absolutely need a SwiftUI API like focusedSceneObject we'll have to hack it into each of the three split views.

Misc:

• Moved the split view setup code inside the split view.

There's still some work to do on the toolbar. In the example video the branch picker disappears before the activity view, which imo should be the other way around. But it's def a step in the right direction.

Related Issues

• closes 🐞 Drag-collapsing Inspector sidebar in full-screen breaks layout #1224
• related feat: Activity Viewer #1769

Checklist

• I read and understood the contributing guide as well as the code of conduct
• The issues this PR addresses are related to each other
• My changes generate no new warnings
• My code builds and runs on my machine
• My changes are all related to the related issue above
• I documented my code

Screenshots

Before:

Toolbar removing wrong view:

Resizing is awful:

Now:

Still works w/ side tabs