fix(cleanup): library scans survive navigation, reconnect on return

The transparency / single-color audit cards held the run + poll timer in
local component state, so navigating away destroyed both and onMounted never
reconnected — the Celery scan kept running and writing LibraryAuditRun, but
the UI forgot it. Now each card, on mount, fetches its rule's latest run
(GET /api/cleanup/audit?rule=<rule>&limit=1) and rehydrates: shows progress +
resumes polling if still running, or shows the completed result (ready/applied/
error) so the operator can act on it after returning. Adds the ?rule= filter
to the audit-history endpoint + cleanup store latestAuditForRule().

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/src/components/cleanup/SingleColorAuditCard.vue

@@ -112,6 +112,16 @@ onMounted(async () => {
   await store.loadDefaults()
   threshold.value = store.defaults.single_color_threshold
   tolerance.value = store.defaults.single_color_tolerance
+  // Reconnect to this rule's latest run so a scan started before navigating
+  // away keeps showing progress / its result on return (the scan itself runs
+  // backend-side regardless).
+  try {
+    const latest = await store.latestAuditForRule('single_color')
+    if (latest) {
+      audit.value = latest
+      if (latest.status === 'running') startPoll(latest.id)
+    }
+  } catch { /* non-fatal — card still works for a fresh scan */ }
 })
 
 onUnmounted(() => stopPoll())

frontend/src/components/cleanup/TransparencyAuditCard.vue

@@ -97,6 +97,16 @@ let pollTimer = null
 onMounted(async () => {
   await store.loadDefaults()
   threshold.value = store.defaults.transparency_threshold
+  // Reconnect to this rule's latest run so a scan started before navigating
+  // away keeps showing progress / its result on return (the scan itself runs
+  // backend-side regardless).
+  try {
+    const latest = await store.latestAuditForRule('transparency')
+    if (latest) {
+      audit.value = latest
+      if (latest.status === 'running') startPoll(latest.id)
+    }
+  } catch { /* non-fatal — card still works for a fresh scan */ }
 })
 
 onUnmounted(() => stopPoll())