refactor(ui): SampleNameGrid primitive for maintenance-card previews (DRY pattern sweep)

The preview sample-name grid (scrollable monospace chip grid) was hand-rolled
5 times with verbatim-duplicated markup + CSS — TagMaintenanceCard (×4) and
PostMaintenanceCard. Consolidate to <SampleNameGrid> (components/common): pass
:names for the plain case, default slot for the normalize from→to chips
(styled via :slotted .fc-name). Removed the duplicated .fc-name-grid/.fc-name
CSS from both cards.

Over-DRY guard: only the verbatim-duplicated grid is merged — each card's
preview/commit logic and result-count lines genuinely differ and stay put;
MinDimensionCard's typed-token confirm is a separate variant, untouched.
§8b: fc-name-grid now lives only in SampleNameGrid. Catalog updated.

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

frontend/src/components/settings/PostMaintenanceCard.vue

@@ -36,11 +36,10 @@
             Nothing to clean up.
           </span>
         </p>
-        <div v-if="preview.sample_names?.length" class="fc-name-grid mb-3">
-          <span v-for="(n, i) in preview.sample_names" :key="i" class="fc-name">
-            {{ n }}
-          </span>
-        </div>
+        <SampleNameGrid
+          v-if="preview.sample_names?.length"
+          :names="preview.sample_names" class="mb-3"
+        />
         <v-btn
           color="error" variant="flat" rounded="pill"
           prepend-icon="mdi-delete-sweep"
@@ -61,6 +60,7 @@
 import { ref } from 'vue'
 
 import { useAdminStore } from '../../stores/admin.js'
+import SampleNameGrid from '../common/SampleNameGrid.vue'
 
 const store = useAdminStore()
 const preview = ref(null)
@@ -94,15 +94,4 @@ async function onCommit() {
 
 <style scoped>
 .fc-post-maint { border-radius: 8px; }
-.fc-name-grid {
-  display: flex; flex-wrap: wrap; gap: 4px 8px;
-  max-height: 200px; overflow-y: auto;
-  padding: 8px; border-radius: 4px;
-  background: rgb(var(--v-theme-surface-light));
-}
-.fc-name {
-  font-family: 'JetBrains Mono', monospace;
-  font-size: 12px;
-  color: rgb(var(--v-theme-on-surface-variant));
-}
 </style>