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/common/SampleNameGrid.vue

@@ -0,0 +1,32 @@
+<template>
+  <!-- Scrollable grid of monospace name chips — the preview "here's a sample of
+       what will change" surface shared by the maintenance cards (DRY pattern
+       sweep 2026-06-09). Pass `names` for the common case; use the default slot
+       to render custom chips (style them `.fc-name` and they inherit the look
+       via :slotted). The caller keeps its own v-if for the empty case. -->
+  <div class="fc-name-grid">
+    <slot>
+      <span v-for="(n, i) in names" :key="i" class="fc-name">{{ n }}</span>
+    </slot>
+  </div>
+</template>
+
+<script setup>
+defineProps({
+  names: { type: Array, default: () => [] },
+})
+</script>
+
+<style scoped>
+.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, :slotted(.fc-name) {
+  font-family: 'JetBrains Mono', monospace;
+  font-size: 12px;
+  color: rgb(var(--v-theme-on-surface-variant));
+}
+</style>

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>

frontend/src/components/settings/TagMaintenanceCard.vue

@@ -31,11 +31,10 @@
             Showing first 50 names.
           </span>
         </p>
-        <div v-if="preview.sample_names?.length" class="fc-name-grid mb-3">
-          <span v-for="n in preview.sample_names" :key="n" 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"
@@ -76,11 +75,10 @@
             {{ p }}: {{ n }}&nbsp;&nbsp;
           </span>
         </p>
-        <div v-if="kindPreview.sample_names?.length" class="fc-name-grid mb-3">
-          <span v-for="n in kindPreview.sample_names" :key="n" class="fc-name">
-            {{ n }}
-          </span>
-        </div>
+        <SampleNameGrid
+          v-if="kindPreview.sample_names?.length"
+          :names="kindPreview.sample_names" class="mb-3"
+        />
         <v-btn
           color="error" variant="flat" rounded="pill"
           prepend-icon="mdi-delete-sweep"
@@ -122,11 +120,10 @@
           across <strong>{{ resetPreview.applications }}</strong> image
           application(s).
         </p>
-        <div v-if="resetPreview.sample_names?.length" class="fc-name-grid mb-3">
-          <span v-for="n in resetPreview.sample_names" :key="n" class="fc-name">
-            {{ n }}
-          </span>
-        </div>
+        <SampleNameGrid
+          v-if="resetPreview.sample_names?.length"
+          :names="resetPreview.sample_names" class="mb-3"
+        />
         <v-btn
           color="error" variant="flat" rounded="pill"
           prepend-icon="mdi-delete-alert"
@@ -170,14 +167,14 @@
           <strong>{{ normPreview.collisions }}</strong> collision(s) merging
           <strong>{{ normPreview.tags_to_merge }}</strong> tag(s) away.
         </p>
-        <div v-if="normPreview.sample?.length" class="fc-name-grid mb-3">
+        <SampleNameGrid v-if="normPreview.sample?.length" class="mb-3">
           <span
             v-for="s in normPreview.sample" :key="s.to + s.kind"
             class="fc-name"
           >
             <template v-if="s.merge">{{ s.from.join(' + ') }} → </template>{{ s.to }}
           </span>
-        </div>
+        </SampleNameGrid>
         <v-btn
           color="error" variant="flat" rounded="pill"
           prepend-icon="mdi-format-letter-case"
@@ -198,6 +195,7 @@
 import { ref } from 'vue'
 
 import { useAdminStore } from '../../stores/admin.js'
+import SampleNameGrid from '../common/SampleNameGrid.vue'
 
 const store = useAdminStore()
 const preview = ref(null)
@@ -304,15 +302,4 @@ async function onNormCommit() {
 
 <style scoped>
 .fc-tag-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>