fix: resync slot layouts when switching between app mode and graph mode (#10273)

## Summary

Fix broken link rendering (noodles disappearing or going to wrong
positions) when switching between app mode and graph mode tabs.

## Changes

- **What**: When the graph canvas is hidden via `display: none` in app
mode, slot elements lose valid DOM measurements. On switching back,
links rendered at stale coordinates or disappeared. This PR rekeys
`LGraphNode` components by workflow path, adds measurability guards to
skip hidden slots, clears stale layouts, and watches `linearMode` to
trigger a full slot layout resync on mode transitions.

## Review Focus

- The `isSlotElementMeasurable` guard skips elements that are
disconnected or have zero-size rects — verify this doesn't inadvertently
skip slots during normal graph rendering.
- The `linearMode` watcher clears all slot layouts when entering app
mode and requests a full resync when leaving — confirm no flicker or
race with the RAF-based sync scheduler.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-10273-fix-resync-slot-layouts-when-switching-between-app-mode-and-graph-mode-3276d73d3650812f9366dae53c7b2d37)
by [Unito](https://www.unito.io)

---------

Co-authored-by: Amp <amp@ampcode.com>

src/components/graph/GraphCanvas.vue

@@ -164,9 +164,11 @@ import { useWorkflowAutoSave } from '@/platform/workflow/persistence/composables
 import { useWorkflowPersistenceV2 as useWorkflowPersistence } from '@/platform/workflow/persistence/composables/useWorkflowPersistenceV2'
 import { useCanvasStore } from '@/renderer/core/canvas/canvasStore'
 import { useCanvasInteractions } from '@/renderer/core/canvas/useCanvasInteractions'
+import { layoutStore } from '@/renderer/core/layout/store/layoutStore'
 import TransformPane from '@/renderer/core/layout/transform/TransformPane.vue'
 import MiniMap from '@/renderer/extensions/minimap/MiniMap.vue'
 import LGraphNode from '@/renderer/extensions/vueNodes/components/LGraphNode.vue'
+import { requestSlotLayoutSyncForAllNodes } from '@/renderer/extensions/vueNodes/composables/useSlotElementTracking'
 import { UnauthorizedError } from '@/scripts/api'
 import { app as comfyApp } from '@/scripts/app'
 import { ChangeTracker } from '@/scripts/changeTracker'
@@ -207,6 +209,7 @@ const workspaceStore = useWorkspaceStore()
 const { isBuilderMode } = useAppMode()
 const canvasStore = useCanvasStore()
 const workflowStore = useWorkflowStore()
+const { linearMode } = storeToRefs(canvasStore)
 const executionStore = useExecutionStore()
 const executionErrorStore = useExecutionErrorStore()
 const toastStore = useToastStore()
@@ -279,6 +282,22 @@ watch(
 const allNodes = computed((): VueNodeData[] =>
   Array.from(vueNodeLifecycle.nodeManager.value?.vueNodeData?.values() ?? [])
 )
+watch(
+  () => linearMode.value,
+  (isLinearMode) => {
+    if (!shouldRenderVueNodes.value) return
+
+    if (isLinearMode) {
+      layoutStore.clearAllSlotLayouts()
+    } else {
+      // App mode hides the graph canvas with `display: none`, so slot connectors
+      // need a fresh DOM measurement pass before links can render correctly.
+      requestSlotLayoutSyncForAllNodes()
+    }
+
+    layoutStore.setPendingSlotSync(true)
+  }
+)
 
 function onLinkOverlayReady(el: HTMLCanvasElement) {
   if (!canvasStore.canvas) return