[refactor] Improve workflow domain organization (#5584)

* [refactor] move workflow domain to its own folder

* [refactor] Fix workflow platform architecture organization

- Move workflow rendering functionality to renderer/thumbnail domain
- Rename ui folder to management for better semantic clarity
- Update all import paths to reflect proper domain boundaries
- Fix test imports to use new structure

Architecture improvements:
- rendering → renderer/thumbnail (belongs with other rendering logic)
- ui → management (better name for state management and UI integration)

This ensures proper separation of concerns and domain boundaries.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

* [fix] Resolve circular dependency between nodeDefStore and subgraphStore

* [fix] Update browser test imports to use new workflow platform paths

---------

Co-authored-by: Claude <noreply@anthropic.com>

src/composables/useCanvasDrop.ts

@@ -3,14 +3,14 @@ import { Ref } from 'vue'
 import { usePragmaticDroppable } from '@/composables/usePragmaticDragAndDrop'
 import { LGraphNode } from '@/lib/litegraph/src/litegraph'
 import { LiteGraph } from '@/lib/litegraph/src/litegraph'
+import { useWorkflowService } from '@/platform/workflow/core/services/workflowService'
+import { ComfyWorkflow } from '@/platform/workflow/management/stores/workflowStore'
 import { app as comfyApp } from '@/scripts/app'
 import { useLitegraphService } from '@/services/litegraphService'
-import { useWorkflowService } from '@/services/workflowService'
 import { ComfyModelDef } from '@/stores/modelStore'
 import { ModelNodeProvider } from '@/stores/modelToNodeStore'
 import { useModelToNodeStore } from '@/stores/modelToNodeStore'
 import { ComfyNodeDefImpl } from '@/stores/nodeDefStore'
-import { ComfyWorkflow } from '@/stores/workflowStore'
 import { RenderedTreeExplorerNode } from '@/types/treeExplorerTypes'
 
 export const useCanvasDrop = (canvasRef: Ref<HTMLCanvasElement>) => {