refactor(dry-F2): centralize shared UI primitives (relative-time, toast, download-status)

- utils/date.js: add formatRelative(iso, {future,nullText}); migrate 6 sites
  (SourceRow, SubscriptionsTab, SourceHealthDot, SchedulerStatusBar +
  thin adapters in BackupRunsTable/SystemActivityTab for their '—' null text).
  PostCard (30d->absolute) and CredentialCard (mo/y buckets) intentionally
  keep bespoke formatters.
- utils/toast.js: toast(opts) wraps the globalThis.window?.__fcToast?.(...)
  incantation; migrate 63 call sites across 24 files.
- utils/downloadStatus.js: single source for the download-event status enum
  -> label/color/icon; collapse the 3 duplicate maps (DownloadStatChips,
  DownloadsFilterPopover, DownloadEventRow).

Net -33 lines. Platform metadata was already centralized in platformColor.js.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/components/cleanup/MinDimensionCard.vue

@@ -62,6 +62,7 @@
 </template>
 
 <script setup>
+import { toast } from '../../utils/toast.js'
 import { onMounted, ref } from 'vue'
 
 import DestructiveConfirmModal from '../modal/DestructiveConfirmModal.vue'
@@ -94,7 +95,7 @@ async function onPreview() {
   try {
     preview.value = await store.previewMinDim(minW.value, minH.value)
   } catch (e) {
-    window.__fcToast?.({ text: `Preview failed: ${e.message}`, type: 'error' })
+    toast({ text: `Preview failed: ${e.message}`, type: 'error' })
   } finally {
     busy.value = false
   }
@@ -108,12 +109,12 @@ function onDeleteClick() {
 async function onConfirmedDelete(token) {
   try {
     const res = await store.deleteMinDim(minW.value, minH.value, token)
-    window.__fcToast?.({
+    toast({
       text: `Deleted ${res.deleted} image(s)`, type: 'success',
     })
     preview.value = null
   } catch (e) {
-    window.__fcToast?.({ text: `Delete failed: ${e.message}`, type: 'error' })
+    toast({ text: `Delete failed: ${e.message}`, type: 'error' })
   }
 }
 </script>

frontend/src/components/cleanup/SingleColorAuditCard.vue

@@ -93,6 +93,7 @@
 </template>
 
 <script setup>
+import { toast } from '../../utils/toast.js'
 import { onMounted, onUnmounted, ref } from 'vue'
 
 import DestructiveConfirmModal from '../modal/DestructiveConfirmModal.vue'
@@ -124,7 +125,7 @@ function startPoll(id) {
       if (fresh.status !== 'running') stopPoll()
     } catch (e) {
       stopPoll()
-      window.__fcToast?.({ text: `Audit poll failed: ${e.message}`, type: 'error' })
+      toast({ text: `Audit poll failed: ${e.message}`, type: 'error' })
     }
   }, 5000)
 }
@@ -142,7 +143,7 @@ async function onStart() {
     audit.value = await store.getAudit(res.audit_id)
     startPoll(res.audit_id)
   } catch (e) {
-    window.__fcToast?.({ text: `Scan start failed: ${e.message}`, type: 'error' })
+    toast({ text: `Scan start failed: ${e.message}`, type: 'error' })
   } finally {
     busy.value = false
   }
@@ -155,7 +156,7 @@ async function onCancel() {
     audit.value = await store.getAudit(audit.value.id)
     stopPoll()
   } catch (e) {
-    window.__fcToast?.({ text: `Cancel failed: ${e.message}`, type: 'error' })
+    toast({ text: `Cancel failed: ${e.message}`, type: 'error' })
   }
 }
 
@@ -167,12 +168,12 @@ function onApplyClick() {
 async function onConfirmedApply(token) {
   try {
     const res = await store.applyAudit(audit.value.id, token)
-    window.__fcToast?.({
+    toast({
       text: `Deleted ${res.deleted} image(s)`, type: 'success',
     })
     audit.value = await store.getAudit(audit.value.id)
   } catch (e) {
-    window.__fcToast?.({ text: `Apply failed: ${e.message}`, type: 'error' })
+    toast({ text: `Apply failed: ${e.message}`, type: 'error' })
   }
 }
 </script>

frontend/src/components/cleanup/TransparencyAuditCard.vue

@@ -80,6 +80,7 @@
 </template>
 
 <script setup>
+import { toast } from '../../utils/toast.js'
 import { onMounted, onUnmounted, ref } from 'vue'
 
 import DestructiveConfirmModal from '../modal/DestructiveConfirmModal.vue'
@@ -109,7 +110,7 @@ function startPoll(id) {
       if (fresh.status !== 'running') stopPoll()
     } catch (e) {
       stopPoll()
-      window.__fcToast?.({ text: `Audit poll failed: ${e.message}`, type: 'error' })
+      toast({ text: `Audit poll failed: ${e.message}`, type: 'error' })
     }
   }, 5000)
 }
@@ -125,7 +126,7 @@ async function onStart() {
     audit.value = await store.getAudit(res.audit_id)
     startPoll(res.audit_id)
   } catch (e) {
-    window.__fcToast?.({ text: `Scan start failed: ${e.message}`, type: 'error' })
+    toast({ text: `Scan start failed: ${e.message}`, type: 'error' })
   } finally {
     busy.value = false
   }
@@ -138,7 +139,7 @@ async function onCancel() {
     audit.value = await store.getAudit(audit.value.id)
     stopPoll()
   } catch (e) {
-    window.__fcToast?.({ text: `Cancel failed: ${e.message}`, type: 'error' })
+    toast({ text: `Cancel failed: ${e.message}`, type: 'error' })
   }
 }
 
@@ -150,12 +151,12 @@ function onApplyClick() {
 async function onConfirmedApply(token) {
   try {
     const res = await store.applyAudit(audit.value.id, token)
-    window.__fcToast?.({
+    toast({
       text: `Deleted ${res.deleted} image(s)`, type: 'success',
     })
     audit.value = await store.getAudit(audit.value.id)
   } catch (e) {
-    window.__fcToast?.({ text: `Apply failed: ${e.message}`, type: 'error' })
+    toast({ text: `Apply failed: ${e.message}`, type: 'error' })
   }
 }
 </script>