feat(catalog) : add admin categories page with MalioDataTable and drawer (first draft)

- Page Nuxt /admin/categories : MalioDataTable + bouton Ajouter
- CategoryDrawer : modes creation / consultation / edition (transition
  auto view -> edit a la 1re modif), validation client RG-1.02/04/05,
  mapping erreurs server 409 (doublon) et 422 (violations)
- CategoryDeleteModal : confirmation suppression (soft delete cote API)
- Types Category, CategoryType, User
- i18n admin.categories.* (titre, table, form, validation, toasts)
- Fix latent : ajout 'categories' a AdminLinkSlug e2e (oubli ERP-47)

Logique fetch inline volontaire au M0 — extraction en composables a
ERP-50 (ticket 0.8). Aucune persistance d'etat de tableau dans l'URL.

frontend/modules/catalog/pages/admin/categories.vue

@@ -0,0 +1,162 @@
+<template>
+    <div>
+        <PageHeader>
+            {{ t('admin.categories.title') }}
+            <template #actions>
+                <MalioButton
+                    v-if="canManage"
+                    :label="t('admin.categories.newCategory')"
+                    icon-name="mdi:add-bold"
+                    icon-position="left"
+                    @click="openCreateDrawer"
+                />
+            </template>
+        </PageHeader>
+
+        <!-- Table des categories : tri par defaut sur Nom ASC (RG-1.10).
+             Tri serveur applique a la requete + tri client en miroir pour
+             la pagination front (volumetrie cible <= 300, cf. spec § 4.1). -->
+        <MalioDataTable
+            :columns="columns"
+            :items="categoryItems"
+            :total-items="categories.length"
+            :row-clickable="true"
+            :empty-message="t('admin.categories.noCategories')"
+            @row-click="onRowClick"
+        />
+
+        <!-- Drawer creation / consultation / edition. -->
+        <CategoryDrawer
+            v-model="drawerOpen"
+            :category="selectedCategory"
+            @saved="onCategorySaved"
+            @delete="onDeleteRequest"
+        />
+
+        <!-- Modale de confirmation suppression (soft delete cote serveur). -->
+        <CategoryDeleteModal
+            v-model="deleteModalOpen"
+            :category-name="categoryToDelete?.name ?? ''"
+            :loading="deleting"
+            @confirm="handleDelete"
+        />
+    </div>
+</template>
+
+<script setup lang="ts">
+import type { Category } from '~/modules/catalog/types/category'
+import type { HydraCollection } from '~/shared/utils/api'
+
+const { t } = useI18n()
+const api = useApi()
+const { can } = usePermissions()
+
+useHead({ title: t('admin.categories.title') })
+
+const canManage = computed(() => can('catalog.categories.manage'))
+
+const categories = ref<Category[]>([])
+const loading = ref(false)
+const drawerOpen = ref(false)
+const selectedCategory = ref<Category | null>(null)
+const deleteModalOpen = ref(false)
+const categoryToDelete = ref<Category | null>(null)
+const deleting = ref(false)
+
+// Colonnes du datatable. Le type est embarque cote API (cf. spec-back § 3.4) —
+// on aplatit en label lisible pour l'affichage.
+const columns = [
+    { key: 'name', label: t('admin.categories.table.name') },
+    { key: 'typeLabel', label: t('admin.categories.table.type') },
+]
+
+const categoryItems = computed(() =>
+    categories.value.map(cat => ({
+        id: cat.id,
+        name: cat.name,
+        typeLabel: cat.categoryType?.label ?? '',
+    })),
+)
+
+function getCategoryById(id: number): Category | undefined {
+    return categories.value.find(c => c.id === id)
+}
+
+function onRowClick(item: Record<string, unknown>) {
+    const category = getCategoryById(item.id as number)
+    if (category) openEditDrawer(category)
+}
+
+/**
+ * Charge la liste des categories. Le serveur exclut les soft-deleted par
+ * defaut (RG-1.08) et trie par name ASC (RG-1.10). Pas de pagination
+ * serveur (RG : volumetrie ≤ 300, pagination front via MalioDataTable).
+ *
+ * Logique inline volontaire au M0 (decision prompt ERP-49) : extraction
+ * en composable `useCategoriesAdmin` au ticket 0.8 (ERP-50).
+ */
+async function loadCategories(): Promise<void> {
+    loading.value = true
+    try {
+        const data = await api.get<HydraCollection<Category>>(
+            '/categories',
+            { itemsPerPage: 999 },
+            { toast: false },
+        )
+        categories.value = data.member ?? []
+    } catch {
+        // Reset sur echec pour ne pas afficher de donnees stale. Pas de
+        // toast : un user sans permission view recoit 403 et voit une
+        // liste vide propre — le mecanisme de gating se fait cote sidebar.
+        categories.value = []
+    } finally {
+        loading.value = false
+    }
+}
+
+function openCreateDrawer() {
+    selectedCategory.value = null
+    drawerOpen.value = true
+}
+
+function openEditDrawer(category: Category) {
+    selectedCategory.value = category
+    drawerOpen.value = true
+}
+
+function onDeleteRequest() {
+    if (!selectedCategory.value) return
+    categoryToDelete.value = selectedCategory.value
+    deleteModalOpen.value = true
+}
+
+/**
+ * DELETE /api/categories/{id} → soft delete (RG-1.12). Le serveur pose
+ * `deleted_at = now()` et retourne 204. Refresh de la liste a la fin
+ * pour retirer la ligne (l'index unique partiel autorise une recreation
+ * ulterieure avec le meme couple (name, type) — RG-1.07).
+ */
+async function handleDelete(): Promise<void> {
+    if (!categoryToDelete.value) return
+    deleting.value = true
+    try {
+        await api.delete(`/categories/${categoryToDelete.value.id}`, {}, {
+            toastSuccessMessage: t('admin.categories.toast.deleted'),
+        })
+        deleteModalOpen.value = false
+        categoryToDelete.value = null
+        drawerOpen.value = false
+        await loadCategories()
+    } finally {
+        deleting.value = false
+    }
+}
+
+function onCategorySaved() {
+    loadCategories()
+}
+
+onMounted(() => {
+    loadCategories()
+})
+</script>