Doc editor and code editor are toggleable docks

[kazcw]

Pull Request Description

Dock improvements:

• Right and bottom docks are toggled with buttons.
• Bottom dock:
  • Fills available width.
  • Height resize handle behaves like right dock's.
• Documentation editor: Top toolbar is outside scrollable area.
• Extended menu: Entries have icons.
• Add component button: Now in bottom-right.

Screen.Recording.2024-07-01.at.09.37.07.mov

Closes #10385, #10386.

Important Notes

• unrefElement: Fixed a type-safety bug in; documented a reactivity limitation.
• keyboardBusy: Fixed a bug where shortcuts were ignored after clicking any button.
• Fixed right-dock slide-in animation.

Checklist

Please ensure that the following checklist has been satisfied before submitting the PR:

• The documentation has been updated, if necessary.
• Screenshots/screencasts have been attached, if there are any visual changes. For interactive or animated visual changes, a screencast is preferred.
• All code follows the
  Scala,
  Java,
  TypeScript,
  and
  Rust
  style guides. In case you are using a language not listed above, follow the Rust style guide.
• Unit tests have been written where possible.

[farmaazon]

We may use withDefaults https://vuejs.org/guide/typescript/composition-api#props-default-values

[kazcw]

I just saw we have a SizeTransition component already, so we don't need this.