feat(settings): tidy Cleanup tab into sectioned compact tiles (pass 1)

The Cleanup + Maintenance sections had ~17 full-width stacked cards with long
descriptions — a hunt to scan. Operator wants compact, sectioned, scannable tiles
(2026-06-18: keep both tabs, group inside, compact tiles in a grid).

New common/MaintenanceTile.vue: a compact expandable tile (icon + short title +
one-line blurb collapsed; click the header to expand the full controls/preview/
result inline; keyboard-accessible button + focus ring;  tints the
icon,  keeps a running task expanded).

Cleanup tab (this pass) restructured into 3 sections — Import-filter audits
(Min dimensions, Transparency, Single-color) / Duplicates & posts (Bare posts,
Duplicate posts, Deduplicate videos, Gated-post previews) / Tags (Unused, Legacy,
Reset content tagging, Standardize casing) — each a responsive grid of tiles.
PostMaintenanceCard split into 2 tiles, TagMaintenanceCard into 4. Moved
VideoDedupCard + GatedPurgeCard from the Maintenance tab here (both are
destructive content cleanup). All card logic unchanged — only the chrome.

Maintenance tab tiling is pass 2 (TODO noted in MaintenancePanel).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/views/CleanupView.vue

@@ -1,16 +1,44 @@
 <template>
   <div class="fc-cleanup">
-    <p class="fc-muted text-body-2 mb-4">
-      Retroactive enforcement of import-filter rules. Each card scans the
-      existing library for content that the current import filters would
-      now exclude. Destructive — typed-token confirmation required.
+    <p class="fc-muted text-body-2 mb-5">
+      Retroactive enforcement and cleanup on the existing library — each tool
+      previews before it acts, and destructive ones need a typed-token confirm.
+      Click a tile to open its controls.
     </p>
 
-    <MinDimensionCard class="mb-4" />
-    <TransparencyAuditCard class="mb-4" />
-    <SingleColorAuditCard class="mb-4" />
-    <PostMaintenanceCard class="mb-4" />
-    <TagMaintenanceCard />
+    <section class="fc-section">
+      <h3 class="fc-section__title">Import-filter audits</h3>
+      <p class="fc-section__hint">
+        Scan for content the current import filters would now exclude.
+      </p>
+      <div class="fc-tile-grid">
+        <MinDimensionCard />
+        <TransparencyAuditCard />
+        <SingleColorAuditCard />
+      </div>
+    </section>
+
+    <section class="fc-section">
+      <h3 class="fc-section__title">Duplicates &amp; posts</h3>
+      <p class="fc-section__hint">
+        Tidy post records, duplicates and locked-preview leftovers.
+      </p>
+      <div class="fc-tile-grid">
+        <PostMaintenanceCard />
+        <VideoDedupCard />
+        <GatedPurgeCard />
+      </div>
+    </section>
+
+    <section class="fc-section">
+      <h3 class="fc-section__title">Tags</h3>
+      <p class="fc-section__hint">
+        Remove unused / legacy tags and standardize the existing set.
+      </p>
+      <div class="fc-tile-grid">
+        <TagMaintenanceCard />
+      </div>
+    </section>
   </div>
 </template>
 
@@ -19,14 +47,31 @@ import MinDimensionCard from '../components/cleanup/MinDimensionCard.vue'
 import TransparencyAuditCard from '../components/cleanup/TransparencyAuditCard.vue'
 import SingleColorAuditCard from '../components/cleanup/SingleColorAuditCard.vue'
 import PostMaintenanceCard from '../components/settings/PostMaintenanceCard.vue'
-// Reuse existing TagMaintenanceCard (FC-3k) as-is — it already handles
-// preview + commit of prune-unused-tags via the admin store. Operator
-// confirmed 2026-05-26: don't duplicate into a new UnusedTagsCard.
-// MaintenancePanel drops its TagMaintenanceCard reference in the
-// SettingsView edit (Task 16) so this is now the sole rendering site.
+import VideoDedupCard from '../components/settings/VideoDedupCard.vue'
+import GatedPurgeCard from '../components/settings/GatedPurgeCard.vue'
 import TagMaintenanceCard from '../components/settings/TagMaintenanceCard.vue'
 </script>
 
 <style scoped>
-.fc-cleanup { max-width: 900px; }
+.fc-cleanup { max-width: 1100px; }
+.fc-section { margin-bottom: 28px; }
+.fc-section__title {
+  font-size: 0.78rem;
+  font-weight: 700;
+  letter-spacing: 0.06em;
+  text-transform: uppercase;
+  color: rgb(var(--v-theme-accent));
+  margin-bottom: 2px;
+}
+.fc-section__hint {
+  font-size: 0.8rem;
+  color: rgb(var(--v-theme-on-surface-variant));
+  margin-bottom: 12px;
+}
+.fc-tile-grid {
+  display: grid;
+  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
+  gap: 14px;
+  align-items: start;
+}
 </style>