[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

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

src/components/searchbox/NodeSearchBoxPopover.vue

@@ -45,11 +45,11 @@ import {
   LiteGraphCanvasEvent
 } from '@/lib/litegraph/src/litegraph'
 import type { CanvasPointerEvent } from '@/lib/litegraph/src/types/events'
+import { useWorkflowStore } from '@/platform/workflow/management/stores/workflowStore'
 import { useCanvasStore } from '@/renderer/core/canvas/canvasStore'
 import { useLitegraphService } from '@/services/litegraphService'
 import { ComfyNodeDefImpl, useNodeDefStore } from '@/stores/nodeDefStore'
 import { useSettingStore } from '@/stores/settingStore'
-import { useWorkflowStore } from '@/stores/workflowStore'
 import { useSearchBoxStore } from '@/stores/workspace/searchBoxStore'
 import { LinkReleaseTriggerAction } from '@/types/searchBoxTypes'
 import { FuseFilterWithValue } from '@/utils/fuseUtil'