[refactor] Migrate manager code to DDD structure (#5662)

## Summary

Reorganized custom nodes manager functionality from scattered technical
layers into a cohesive domain-focused module following [domain-driven
design](https://en.wikipedia.org/wiki/Domain-driven_design) principles.

## Changes

- **What**: Migrated all manager code from technical layers
(`src/components/`, `src/stores/`, etc.) to unified domain structure at
`src/workbench/extensions/manager/`
- **Breaking**: Import paths changed for all manager-related modules
(40+ files updated)

## Review Focus

Verify all import path updates are correct and no circular dependencies
introduced. Check that [Vue 3 composition
API](https://vuejs.org/guide/reusability/composables.html) patterns
remain consistent across relocated composables.


┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-5662-refactor-Migrate-manager-code-to-DDD-structure-2736d73d3650812c87faf6ed0fffb196)
by [Unito](https://www.unito.io)

src/workbench/extensions/manager/composables/useManagerState.ts

@@ -0,0 +1,208 @@
+import { storeToRefs } from 'pinia'
+import { computed, readonly } from 'vue'
+
+import { t } from '@/i18n'
+import { useToastStore } from '@/platform/updates/common/toastStore'
+import { api } from '@/scripts/api'
+import { useDialogService } from '@/services/dialogService'
+import { useCommandStore } from '@/stores/commandStore'
+import { useSystemStatsStore } from '@/stores/systemStatsStore'
+import { ManagerTab } from '@/workbench/extensions/manager/types/comfyManagerTypes'
+
+export enum ManagerUIState {
+  DISABLED = 'disabled',
+  LEGACY_UI = 'legacy',
+  NEW_UI = 'new'
+}
+
+export function useManagerState() {
+  const systemStatsStore = useSystemStatsStore()
+  const { systemStats, isInitialized: systemInitialized } =
+    storeToRefs(systemStatsStore)
+
+  /**
+   * The current manager UI state.
+   * Computed once and cached until dependencies change (which they don't during runtime).
+   * This follows Vue's conventions and provides better performance through caching.
+   */
+  const managerUIState = readonly(
+    computed((): ManagerUIState => {
+      // Wait for systemStats to be initialized
+      if (!systemInitialized.value) {
+        // Default to DISABLED while loading
+        return ManagerUIState.DISABLED
+      }
+
+      // Get current values
+      const clientSupportsV4 =
+        api.getClientFeatureFlags().supports_manager_v4_ui ?? false
+
+      const serverSupportsV4 = api.getServerFeature(
+        'extension.manager.supports_v4'
+      )
+
+      // Check command line args first (highest priority)
+      // --enable-manager flag enables the manager (opposite of old --disable-manager)
+      const hasEnableManager =
+        systemStats.value?.system?.argv?.includes('--enable-manager')
+
+      // If --enable-manager is NOT present, manager is disabled
+      if (!hasEnableManager) {
+        return ManagerUIState.DISABLED
+      }
+
+      if (
+        systemStats.value?.system?.argv?.includes('--enable-manager-legacy-ui')
+      ) {
+        return ManagerUIState.LEGACY_UI
+      }
+
+      // Both client and server support v4 = NEW_UI
+      if (clientSupportsV4 && serverSupportsV4 === true) {
+        return ManagerUIState.NEW_UI
+      }
+
+      // Server supports v4 but client doesn't = LEGACY_UI
+      if (serverSupportsV4 === true && !clientSupportsV4) {
+        return ManagerUIState.LEGACY_UI
+      }
+
+      // Server explicitly doesn't support v4 = LEGACY_UI
+      if (serverSupportsV4 === false) {
+        return ManagerUIState.LEGACY_UI
+      }
+
+      // If server feature flags haven't loaded yet, default to NEW_UI
+      // This is a temporary state - feature flags are exchanged immediately on WebSocket connection
+      // NEW_UI is the safest default since v2 API is the current standard
+      // If the server doesn't support v2, API calls will fail with 404 and be handled gracefully
+      if (serverSupportsV4 === undefined) {
+        return ManagerUIState.NEW_UI
+      }
+
+      // Should never reach here, but if we do, disable manager
+      return ManagerUIState.DISABLED
+    })
+  )
+
+  /**
+   * Check if manager is enabled (not DISABLED)
+   */
+  const isManagerEnabled = readonly(
+    computed((): boolean => {
+      return managerUIState.value !== ManagerUIState.DISABLED
+    })
+  )
+
+  /**
+   * Check if manager UI is in NEW_UI mode
+   */
+  const isNewManagerUI = readonly(
+    computed((): boolean => {
+      return managerUIState.value === ManagerUIState.NEW_UI
+    })
+  )
+
+  /**
+   * Check if manager UI is in LEGACY_UI mode
+   */
+  const isLegacyManagerUI = readonly(
+    computed((): boolean => {
+      return managerUIState.value === ManagerUIState.LEGACY_UI
+    })
+  )
+
+  /**
+   * Check if install button should be shown (only in NEW_UI mode)
+   */
+  const shouldShowInstallButton = readonly(
+    computed((): boolean => {
+      return isNewManagerUI.value
+    })
+  )
+
+  /**
+   * Check if manager buttons should be shown (when manager is not disabled)
+   */
+  const shouldShowManagerButtons = readonly(
+    computed((): boolean => {
+      return isManagerEnabled.value
+    })
+  )
+
+  /**
+   * Opens the manager UI based on current state
+   * Centralizes the logic for opening manager across the app
+   * @param options - Optional configuration for opening the manager
+   * @param options.initialTab - Initial tab to show (for NEW_UI mode)
+   * @param options.legacyCommand - Legacy command to execute (for LEGACY_UI mode)
+   * @param options.showToastOnLegacyError - Whether to show toast on legacy command failure
+   * @param options.isLegacyOnly - If true, shows error in NEW_UI mode instead of opening manager
+   */
+  const openManager = async (options?: {
+    initialTab?: ManagerTab
+    legacyCommand?: string
+    showToastOnLegacyError?: boolean
+    isLegacyOnly?: boolean
+  }): Promise<void> => {
+    const state = managerUIState.value
+    const dialogService = useDialogService()
+    const commandStore = useCommandStore()
+
+    switch (state) {
+      case ManagerUIState.DISABLED:
+        dialogService.showSettingsDialog('extension')
+        break
+
+      case ManagerUIState.LEGACY_UI: {
+        const command =
+          options?.legacyCommand || 'Comfy.Manager.Menu.ToggleVisibility'
+        try {
+          await commandStore.execute(command)
+        } catch {
+          // If legacy command doesn't exist
+          if (options?.showToastOnLegacyError !== false) {
+            useToastStore().add({
+              severity: 'error',
+              summary: t('g.error'),
+              detail: t('manager.legacyMenuNotAvailable'),
+              life: 3000
+            })
+          }
+          // Fallback to extensions panel if not showing toast
+          if (options?.showToastOnLegacyError === false) {
+            dialogService.showSettingsDialog('extension')
+          }
+        }
+        break
+      }
+
+      case ManagerUIState.NEW_UI:
+        if (options?.isLegacyOnly) {
+          // Legacy command is not available in NEW_UI mode
+          useToastStore().add({
+            severity: 'error',
+            summary: t('g.error'),
+            detail: t('manager.legacyMenuNotAvailable'),
+            life: 3000
+          })
+          dialogService.showManagerDialog({ initialTab: ManagerTab.All })
+        } else {
+          dialogService.showManagerDialog(
+            options?.initialTab ? { initialTab: options.initialTab } : undefined
+          )
+        }
+        break
+    }
+  }
+
+  return {
+    managerUIState,
+    isManagerEnabled,
+    isNewManagerUI,
+    isLegacyManagerUI,
+    shouldShowInstallButton,
+    shouldShowManagerButtons,
+    openManager
+  }
+}