feat(ui) : clickable entity links, site→machines links, DataTable fixedLayout

- Add NuxtLink on component/piece/product names in machine hierarchy
  (using composantId, pieceId, product.id)
- Make site machine count badges clickable → /machines?sites={id}
- Add opt-in fixedLayout prop and minWidth to DataTable columns

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/app/components/ComponentItem.vue

@@ -30,7 +30,15 @@
       <div class="flex-1 min-w-0">
         <div class="flex items-center gap-2 flex-wrap">
           <h3 class="text-sm font-semibold truncate" :class="component.pendingEntity ? 'text-error' : 'text-base-content'">
-            {{ component.name }}
+            <NuxtLink
+              v-if="!isEditMode && !component.pendingEntity && component.composantId"
+              :to="`/component/${component.composantId}`"
+              class="hover:underline hover:text-primary transition-colors"
+              @click.stop
+            >
+              {{ component.name }}
+            </NuxtLink>
+            <span v-else>{{ component.name }}</span>
           </h3>
           <button
             v-if="component.pendingEntity"