refactor: expose download phase from composable, fix library-select gate

- Add `phase` (none/active/stopped) to useElectronDownload so consumers
  don't have to duplicate the DownloadStatus taxonomy. The classification
  now lives with the rest of the electronDownload domain.
- MissingModelRow: replace activeElectronDownload/stoppedElectronDownload
  computeds with the phase discriminator.
- Fix the library-select gate: previously `!electronDownload` left the
  combo permanently hidden for any URL that had ever started a download
  (including completed, cancelled, and errored states that still hold a
  store entry). Tighten to `phase === 'none'` so the combo reappears when
  the Download button does — matching the intended mutual-exclusivity with
  progress/stopped notice.

src/platform/electronDownload/composables/useElectronDownload.ts

@@ -1,8 +1,22 @@
+import { DownloadStatus } from '@comfyorg/comfyui-electron-types'
 import { computed, toValue } from 'vue'
 import type { MaybeRefOrGetter } from 'vue'
 
 import { useElectronDownloadStore } from '@/platform/electronDownload/electronDownloadStore'
 
+/**
+ * Classification of the download's current status from a UI-slot perspective:
+ * - `none`    — no entry exists for this URL; render the Download action.
+ * - `active`  — download is live (pending/in-progress/paused/completed);
+ *               render the progress UI.
+ * - `stopped` — download finished in a non-success terminal state
+ *               (cancelled/error); render the stopped notice.
+ *
+ * Exposed from the composable so consumers don't have to duplicate the
+ * DownloadStatus taxonomy.
+ */
+export type ElectronDownloadPhase = 'none' | 'active' | 'stopped'
+
 export function useElectronDownload(url: MaybeRefOrGetter<string | undefined>) {
   const store = useElectronDownloadStore()
 
@@ -11,6 +25,18 @@ export function useElectronDownload(url: MaybeRefOrGetter<string | undefined>) {
     return value ? store.findByUrl(value) : undefined
   })
 
+  const phase = computed<ElectronDownloadPhase>(() => {
+    const dl = download.value
+    if (!dl) return 'none'
+    if (
+      dl.status === DownloadStatus.CANCELLED ||
+      dl.status === DownloadStatus.ERROR
+    ) {
+      return 'stopped'
+    }
+    return 'active'
+  })
+
   const withUrl = (action: (url: string) => unknown) => () => {
     const value = toValue(url)
     if (value) action(value)
@@ -18,6 +44,7 @@ export function useElectronDownload(url: MaybeRefOrGetter<string | undefined>) {
 
   return {
     download,
+    phase,
     pause: withUrl(store.pause),
     resume: withUrl(store.resume),
     cancel: withUrl(store.cancel),

src/platform/missingModel/components/MissingModelRow.vue

@@ -152,13 +152,13 @@
           class="flex w-full items-start py-1"
         >
           <ElectronDownloadProgress
-            v-if="activeElectronDownload"
-            :download="activeElectronDownload"
+            v-if="electronDownloadPhase === 'active' && electronDownload"
+            :download="electronDownload"
             class="w-full"
           />
           <ElectronDownloadStoppedNotice
-            v-else-if="stoppedElectronDownload"
-            :download="stoppedElectronDownload"
+            v-else-if="electronDownloadPhase === 'stopped' && electronDownload"
+            :download="electronDownload"
             @retry="handleDownload"
           />
           <Button
@@ -182,7 +182,7 @@
 
         <TransitionCollapse>
           <MissingModelLibrarySelect
-            v-if="!urlInputs[modelKey] && !electronDownload"
+            v-if="!urlInputs[modelKey] && electronDownloadPhase === 'none'"
             :model-value="getComboValue(model.representative)"
             :options="comboOptions"
             :show-divider="isAssetSupported || downloadable"
@@ -244,22 +244,8 @@ const modelKey = computed(() =>
   getModelStateKey(model.name, directory, isAssetSupported)
 )
 
-const { download: electronDownload } = useElectronDownload(
-  () => model.representative.url
-)
-
-const activeElectronDownload = computed(() => {
-  const dl = electronDownload.value
-  if (!dl) return undefined
-  if (dl.status === 'cancelled' || dl.status === 'error') return undefined
-  return dl
-})
-
-const stoppedElectronDownload = computed(() => {
-  const dl = electronDownload.value
-  if (dl?.status === 'cancelled' || dl?.status === 'error') return dl
-  return undefined
-})
+const { download: electronDownload, phase: electronDownloadPhase } =
+  useElectronDownload(() => model.representative.url)
 
 const downloadStatus = computed(() => getDownloadStatus(modelKey.value))
 const comboOptions = computed(() => getComboOptions(model.representative))