feat(ui) : add UsedInSection showing reverse entity relationships on detail pages

frontend/app/components/common/UsedInSection.vue

@@ -0,0 +1,49 @@
+<template>
+  <div v-if="!loading && totalCount > 0" class="space-y-3 rounded-lg border border-base-200 bg-base-200/30 p-4">
+    <h3 class="font-semibold text-base-content">Utilisé dans</h3>
+
+    <div v-if="data.machines.length" class="space-y-1">
+      <p class="text-xs font-medium text-base-content/60 uppercase tracking-wide">Machines</p>
+      <div v-for="m in data.machines" :key="m.id" class="flex items-center gap-2 text-sm">
+        <NuxtLink :to="`/machine/${m.id}`" class="hover:underline hover:text-primary transition-colors font-medium">
+          {{ m.name }}
+        </NuxtLink>
+        <span v-if="m.site?.name" class="badge badge-ghost badge-xs">{{ m.site.name }}</span>
+      </div>
+    </div>
+
+    <div v-if="data.composants.length" class="space-y-1">
+      <p class="text-xs font-medium text-base-content/60 uppercase tracking-wide">Composants</p>
+      <div v-for="c in data.composants" :key="c.id" class="text-sm">
+        <NuxtLink :to="`/component/${c.id}`" class="hover:underline hover:text-primary transition-colors font-medium">
+          {{ c.name }}
+        </NuxtLink>
+      </div>
+    </div>
+
+    <div v-if="data.pieces.length" class="space-y-1">
+      <p class="text-xs font-medium text-base-content/60 uppercase tracking-wide">Pièces</p>
+      <div v-for="p in data.pieces" :key="p.id" class="text-sm">
+        <NuxtLink :to="`/piece/${p.id}`" class="hover:underline hover:text-primary transition-colors font-medium">
+          {{ p.name }}
+        </NuxtLink>
+      </div>
+    </div>
+  </div>
+
+  <div v-else-if="loading" class="flex justify-center py-4">
+    <span class="loading loading-spinner loading-sm" />
+  </div>
+</template>
+
+<script setup lang="ts">
+const props = defineProps<{
+  entityType: string
+  entityId: string | null
+}>()
+
+const { data, loading, totalCount } = useUsedIn(
+  computed(() => props.entityType),
+  computed(() => props.entityId),
+)
+</script>