⛔ Support maximizing the panel when justified (fix #271356)

[bpasero]

An opus production.

Bugs:

• when panel is maximized you cannot click the close icon to close it
• when panel is maximized you cannot toggle its visibility (e.g. from the title toolbar)
• when auxiliary bar is maximized and toggling it (e.g. from the title toolbar), the entire workbench becomes blank

[Copilot]

Pull request overview

This PR enables panel maximization for all panel alignment modes (left, right, justify, and center), removing the previous restriction that only allowed maximization for center-aligned panels. This addresses issue #271356.

Changes:

• Removed preconditions and checks that prevented panel maximization with non-center alignments
• Enhanced panel maximization logic to hide/show sidebars when using non-center alignments
• Added state management to restore sidebar and auxiliary bar visibility when unmaximizing

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/vs/workbench/browser/parts/panel/panelActions.ts	Removed precondition restrictions and runtime warning for non-center panel maximization; cleaned up unused imports
src/vs/workbench/browser/layout.ts	Refactored setPanelMaximized to support all alignments by hiding/restoring sidebars for non-center alignments; added visibility state tracking and transition guard
src/vs/workbench/browser/actions/layoutActions.ts	Removed precondition that prevented toggling editor visibility with non-center panel alignment; removed unused import

[Copilot]

The optional chaining operator (state?.) is unnecessary here because assertReturnsDefined on line 2176 guarantees that state is defined. Remove the optional chaining to use state.sideBarVisible and state.auxiliaryBarVisible directly, consistent with the similar code pattern in the auxiliary bar implementation (line 2096-2098).

Suggested change

	this.setSideBarHidden(!state?.sideBarVisible);
	this.setAuxiliaryBarHidden(!state?.auxiliaryBarVisible);
	this.setSideBarHidden(!state.sideBarVisible);
	this.setAuxiliaryBarHidden(!state.auxiliaryBarVisible);