Feature: MDI (Multi Document Interface) with tabs

Current State

The editor can only open one asset at a time. Users cannot work on multiple assets simultaneously.

Tasks:

• Implement a tabbed document interface (MDI) for opening multiple assets
• Support opening different asset types in their respective editors across tabs
• Add tab management: close, reorder, drag-and-drop between tab areas
• Preserve unsaved changes indicator per tab
• Possibility to track, via settings api, recently opened files and restore tab state on restart
• evaluate the alternatives: duplicate the internal panels (scene viewport, scene hierarchy, inspector, etc) or resuse them but preserve their state when tab navigation

Acceptance Criteria:

• Multiple assets can be opened simultaneously in separate tabs
• Each tab hosts the appropriate editor for the asset type
• Tabs can be closed, reordered, and show unsaved changes indicator
• Panels (scene viewport, scene hierarchy, inspector, etc) state is persisted across tab navigation
• Tab state is persisted across editor sessions

Related: