Replace the placeholder diagram editor with a professional Studio layout featuring
an interactive @xyflow/react canvas, unified graph data model with bidirectional
converters, Zustand state management, and oklch design tokens. Includes 25 unit
tests for converters and store, with all code review fixes applied.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Add sortOrder column to diagrams, extend PATCH endpoint with projectId
and sortOrder fields, add POST /diagrams/reorder bulk endpoint with
ownership verification and duplicate ID validation. Enhance RecentList
with lastAiMessage preview subtitle. Implement @dnd-kit drag-and-drop
in ProjectTree sidebar with cross-project moves, intra-project reorder,
optimistic updates, drag overlay, drop indicators, and keyboard/pointer
sensor support. Context-aware GET ordering: sortOrder for project views,
updatedAt for recent/all views. 141 tests pass.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>