feat: detect and resolve missing media inputs in error tab (#10309)

## Summary

Add detection and resolution UI for missing image/video/audio inputs
(LoadImage, LoadVideo, LoadAudio nodes) in the Errors tab, mirroring the
existing missing model pipeline.

## Changes

- **What**: New `src/platform/missingMedia/` module — scan pipeline
detects missing media files on workflow load (sync for OSS, async for
cloud), surfaces them in the error tab with upload dropzone, thumbnail
library select, and 2-step confirm flow
- **Detection**: `scanAllMediaCandidates()` checks combo widget values
against options; cloud path defers to `verifyCloudMediaCandidates()` via
`assetsStore.updateInputs()`
- **UI**: `MissingMediaCard` groups by media type; `MissingMediaRow`
shows node name (single) or filename+count (multiple), upload dropzone
with drag & drop, `MissingMediaLibrarySelect` with image/video
thumbnails
- **Resolution**: Upload via `/upload/image` API or select from library
→ status card → checkmark confirm → widget value applied, item removed
from error list
- **Integration**: `executionErrorStore` aggregates into
`hasAnyError`/`totalErrorCount`; `useNodeErrorFlagSync` flags nodes on
canvas; `useErrorGroups` renders in error tab
- **Shared**: Extract `ACCEPTED_IMAGE_TYPES`/`ACCEPTED_VIDEO_TYPES` to
`src/utils/mediaUploadUtil.ts`; extract `resolveComboValues` to
`src/utils/litegraphUtil.ts` (shared across missingMedia + missingModel
scan)
- **Reverse clearing**: Widget value changes on nodes auto-remove
corresponding missing media errors (via `clearWidgetRelatedErrors`)

## Testing

### Unit tests (22 tests)
- `missingMediaScan.test.ts` (12): groupCandidatesByName,
groupCandidatesByMediaType (ordering, multi-name),
verifyCloudMediaCandidates (missing/present, abort before/after
updateInputs, already resolved true/false, no-pending skip, updateInputs
spy)
- `missingMediaStore.test.ts` (10): setMissingMedia, clearMissingMedia
(full lifecycle with interaction state), missingMediaNodeIds,
hasMissingMediaOnNode, removeMissingMediaByWidget
(match/no-match/last-entry), createVerificationAbortController

### E2E tests (10 scenarios in `missingMedia.spec.ts`)
- Detection: error overlay shown, Missing Inputs group in errors tab,
correct row count, dropzone + library select visibility, no false
positive for valid media
- Upload flow: file picker → uploading status card → confirm → row
removed
- Library select: dropdown → selected status card → confirm → row
removed
- Cancel: pending selection → returns to upload/library UI
- All resolved: Missing Inputs group disappears
- Locate node: canvas pans to missing media node

## Review Focus

- Cloud verification path: `verifyCloudMediaCandidates` compares widget
value against `asset_hash` — implicit contract
- 2-step confirm mirrors missing model pattern (`pendingSelection` →
confirm/cancel)
- Event propagation guard on dropzone (`@drop.prevent.stop`) to prevent
canvas LoadImage node creation
- `clearAllErrors()` intentionally does NOT clear missing media (same as
missing models — preserves pending repairs)
- `runMissingMediaPipeline` is now `async` and `await`-ed, matching
model pipeline

## Test plan

- [x] OSS: load workflow with LoadImage referencing non-existent file →
error tab shows it
- [x] Upload file via dropzone → status card shows "Uploaded" → confirm
→ widget updated, error removed
- [x] Select from library with thumbnail preview → confirm → widget
updated, error removed
- [x] Cancel pending selection → returns to upload/library UI
- [x] Load workflow with valid images → no false positives
- [x] Click locate-node → canvas navigates to the node
- [x] Multiple nodes referencing different missing files → correct row
count
- [x] Widget value change on node → missing media error auto-removed

## Screenshots


https://github.com/user-attachments/assets/631c0cb0-9706-4db2-8615-f24a4c3fe27d

src/composables/graph/useNodeErrorFlagSync.ts

@@ -3,6 +3,7 @@ import { computed, watch } from 'vue'
 
 import type { LGraph, LGraphNode } from '@/lib/litegraph/src/litegraph'
 import type { useMissingModelStore } from '@/platform/missingModel/missingModelStore'
+import type { useMissingMediaStore } from '@/platform/missingMedia/missingMediaStore'
 import { useSettingStore } from '@/platform/settings/settingStore'
 import { app } from '@/scripts/app'
 import type { NodeError } from '@/schemas/apiSchema'
@@ -32,7 +33,8 @@ function setNodeHasErrors(node: LGraphNode, hasErrors: boolean): void {
 function reconcileNodeErrorFlags(
   rootGraph: LGraph,
   nodeErrors: Record<string, NodeError> | null,
-  missingModelExecIds: Set<string>
+  missingModelExecIds: Set<string>,
+  missingMediaExecIds: Set<string> = new Set()
 ): void {
   // Collect nodes and slot info that should be flagged
   // Includes both error-owning nodes and their ancestor containers
@@ -64,6 +66,11 @@ function reconcileNodeErrorFlags(
     if (node) flaggedNodes.add(node)
   }
 
+  for (const execId of missingMediaExecIds) {
+    const node = getNodeByExecutionId(rootGraph, execId)
+    if (node) flaggedNodes.add(node)
+  }
+
   forEachNode(rootGraph, (node) => {
     setNodeHasErrors(node, flaggedNodes.has(node))
 
@@ -78,7 +85,8 @@ function reconcileNodeErrorFlags(
 
 export function useNodeErrorFlagSync(
   lastNodeErrors: Ref<Record<string, NodeError> | null>,
-  missingModelStore: ReturnType<typeof useMissingModelStore>
+  missingModelStore: ReturnType<typeof useMissingModelStore>,
+  missingMediaStore: ReturnType<typeof useMissingMediaStore>
 ): () => void {
   const settingStore = useSettingStore()
   const showErrorsTab = computed(() =>
@@ -89,12 +97,13 @@ export function useNodeErrorFlagSync(
     [
       lastNodeErrors,
       () => missingModelStore.missingModelNodeIds,
+      () => missingMediaStore.missingMediaNodeIds,
       showErrorsTab
     ],
     () => {
       if (!app.isGraphReady) return
-      // Legacy (LGraphNode) only: suppress missing-model error flags when
-      // the Errors tab is hidden, since legacy nodes lack the per-widget
+      // Legacy (LGraphNode) only: suppress missing-model/media error flags
+      // when the Errors tab is hidden, since legacy nodes lack the per-widget
       // red highlight that Vue nodes use to indicate *why* a node has errors.
       // Vue nodes compute hasAnyError independently and are unaffected.
       reconcileNodeErrorFlags(
@@ -102,6 +111,9 @@ export function useNodeErrorFlagSync(
         lastNodeErrors.value,
         showErrorsTab.value
           ? missingModelStore.missingModelAncestorExecutionIds
+          : new Set(),
+        showErrorsTab.value
+          ? missingMediaStore.missingMediaAncestorExecutionIds
           : new Set()
       )
     },