Editor: Phase 5 - Advanced Features (UX & productivity)

[neumaennl]

Summary:
Implement advanced UX and productivity features: drag/drop, copy/paste, inline editing, batch operations, refactoring. (ADR 001)

Related ADR:

• docs/architecture/001-editor-transition.md — Phase 5

Acceptance criteria:

• Drag-and-drop for nodes and attributes
• Copy/paste/duplicate nodes
• Keyboard shortcuts for frequent actions
• Batch operations and schema refactoring

Tasks:

• Drag-and-drop functional for nodes and attributes
• Copy/paste/duplicate UI & logic
• Keyboard shortcuts available for core actions
• Inline editing (double-click to rename)
• Batch operations (multi-delete, bulk property changes)
• Validation feedback in UI with actionable messages