refactor: desktop code quality — state encapsulation, DRY grids, ARIA accessibility

[MCERQUA]

Code Quality Issues

Global State (13 variables)

Wrap in a single state object for encapsulation and testability.

Duplicate Explorer Grids

Three near-identical loops build explorer/folder/recycle grids. Extract to shared buildItemGrid() function.

Dead Code

• Line 2223: onclick="history.length" does nothing
• Line 2224: onclick="" empty forward button

ARIA Accessibility

Missing throughout:

• No aria-label on icon buttons or window controls
• No role="dialog" / aria-modal on modals
• No role="menuitem" on context menu items
• No keyboard focus management for windows

Mobile Breakpoint Mismatch

JS uses 480/1024px, CSS uses 400/600px. Must align.

Reference

• Refactor Plan
• Implementation Guide