fix: stabilize nested subgraph promoted widget resolution (#9282)

## Summary

Fix multiple issues with promoted widget resolution in nested subgraphs,
ensuring correct value propagation, slot matching, and rendering for
deeply nested promoted widgets.

## Changes

- **What**: Stabilize nested subgraph promoted widget resolution chain
- Use deep source keys for promoted widget values in Vue rendering mode
- Resolve effective widget options from the source widget instead of the
promoted view
  - Stabilize slot resolution for nested promoted widgets
  - Preserve combo value rendering for promoted subgraph widgets
- Prevent subgraph definition deletion while other nodes still reference
the same type
  - Clean up unused exported resolution types

## Review Focus

- `resolveConcretePromotedWidget.ts` — new recursive resolution logic
for deeply nested promoted widgets
- `useGraphNodeManager.ts` — option extraction now uses
`effectiveWidget` for promoted widgets
- `SubgraphNode.ts` — unpack no longer force-deletes definitions
referenced by other nodes

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-9282-fix-stabilize-nested-subgraph-promoted-widget-resolution-3146d73d365081208a4fe931bb7569cf)
by [Unito](https://www.unito.io)

---------

Co-authored-by: Amp <amp@ampcode.com>
Co-authored-by: GitHub Action <action@github.com>

browser_tests/tests/interaction.spec.ts

@@ -171,6 +171,7 @@ test.describe('Node Interaction', () => {
 
   test('Can drag node', { tag: '@screenshot' }, async ({ comfyPage }) => {
     await comfyPage.nodeOps.dragTextEncodeNode2()
+    await comfyPage.nextFrame()
     await expect(comfyPage.canvas).toHaveScreenshot('dragged-node1.png')
   })
 

browser_tests/tests/subgraphPromotion.spec.ts

@@ -555,6 +555,74 @@ test.describe(
       })
     })
 
+    test.describe('Nested Promoted Widget Disabled State', () => {
+      test('Externally linked promoted widget is disabled, unlinked ones are not', async ({
+        comfyPage
+      }) => {
+        await comfyPage.workflow.loadWorkflow(
+          'subgraphs/subgraph-nested-promotion'
+        )
+        await comfyPage.nextFrame()
+
+        // Node 5 (Sub 0) has 4 promoted widgets. The first (string_a) has its
+        // slot connected externally from the Outer node, so it should be
+        // disabled. The remaining promoted textarea widgets (value, value_1)
+        // are unlinked and should be enabled.
+        const promotedNames = await getPromotedWidgetNames(comfyPage, '5')
+        expect(promotedNames).toContain('string_a')
+        expect(promotedNames).toContain('value')
+
+        const disabledState = await comfyPage.page.evaluate(() => {
+          const node = window.app!.canvas.graph!.getNodeById('5')
+          return (node?.widgets ?? []).map((w) => ({
+            name: w.name,
+            disabled: !!w.computedDisabled
+          }))
+        })
+
+        const linkedWidget = disabledState.find((w) => w.name === 'string_a')
+        expect(linkedWidget?.disabled).toBe(true)
+
+        const unlinkedWidgets = disabledState.filter(
+          (w) => w.name !== 'string_a'
+        )
+        for (const w of unlinkedWidgets) {
+          expect(w.disabled).toBe(false)
+        }
+      })
+
+      test('Unlinked promoted textarea widgets are editable on the subgraph exterior', async ({
+        comfyPage
+      }) => {
+        await comfyPage.workflow.loadWorkflow(
+          'subgraphs/subgraph-nested-promotion'
+        )
+        await comfyPage.nextFrame()
+
+        // The promoted textareas that are NOT externally linked should be
+        // fully opaque and interactive.
+        const textareas = comfyPage.page.getByTestId(
+          TestIds.widgets.domWidgetTextarea
+        )
+        await expect(textareas.first()).toBeVisible()
+
+        const count = await textareas.count()
+        for (let i = 0; i < count; i++) {
+          const textarea = textareas.nth(i)
+          const wrapper = textarea.locator('..')
+          const opacity = await wrapper.evaluate(
+            (el) => getComputedStyle(el).opacity
+          )
+
+          if (opacity === '1' && (await textarea.isEditable())) {
+            const testContent = `nested-promotion-edit-${i}`
+            await textarea.fill(testContent)
+            await expect(textarea).toHaveValue(testContent)
+          }
+        }
+      })
+    })
+
     test.describe('Promotion Cleanup', () => {
       test('Removing subgraph node clears promotion store entries', async ({
         comfyPage