[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/components/topbar/WorkflowTabs.vue

@@ -81,11 +81,14 @@ import { useI18n } from 'vue-i18n'
 
 import WorkflowTab from '@/components/topbar/WorkflowTab.vue'
 import { useOverflowObserver } from '@/composables/element/useOverflowObserver'
-import { useWorkflowService } from '@/services/workflowService'
+import { useWorkflowService } from '@/platform/workflow/core/services/workflowService'
+import {
+  ComfyWorkflow,
+  useWorkflowBookmarkStore
+} from '@/platform/workflow/management/stores/workflowStore'
+import { useWorkflowStore } from '@/platform/workflow/management/stores/workflowStore'
 import { useCommandStore } from '@/stores/commandStore'
 import { useSettingStore } from '@/stores/settingStore'
-import { ComfyWorkflow, useWorkflowBookmarkStore } from '@/stores/workflowStore'
-import { useWorkflowStore } from '@/stores/workflowStore'
 import { useWorkspaceStore } from '@/stores/workspaceStore'
 import { isElectron } from '@/utils/envUtil'
 import { whileMouseDown } from '@/utils/mouseDownUtil'