feat(auth): implement role-based access control (RBAC)

Add roles, permissions, and user_roles tables with default seed data
Protect backend API endpoints with granular permission checks
Add admin UI for managing users, roles, and permissions
Update frontend views to conditionally render actions based on permissions

frontend/src/views/RecipeDetail.vue

@@ -11,14 +11,16 @@ import PageHeader from '../components/PageHeader.vue';
 import Skeleton from '../components/Skeleton.vue';
 import Tabs, { type TabOption } from '../components/Tabs.vue';
 import { iconBack, iconEdit, iconRecipe } from '../icons';
-import { api, type RecipeDetail } from '../services/api';
+import { api, getAuthToken, type AuthUser, type RecipeDetail } from '../services/api';
 import RecipeEdit from './RecipeEdit.vue';
 
 const route = useRoute();
 const { t } = useI18n();
 const recipe = ref<RecipeDetail | null>(null);
+const currentUser = ref<AuthUser | null>(null);
 const detailTab = ref('details');
 const showEditor = computed(() => route.name === 'recipe-edit');
+const canUpdateRecipe = computed(() => currentUser.value?.permissions.includes('recipes.update') === true);
 const detailTabs = computed<TabOption[]>(() => [
   { value: 'details', label: t('common.details') },
   { value: 'discussion', label: t('discussion.title') },
@@ -44,6 +46,13 @@ async function loadRecipeDetail() {
 }
 
 onMounted(async () => {
+  if (getAuthToken()) {
+    try {
+      currentUser.value = (await api.me()).user;
+    } catch {
+      currentUser.value = null;
+    }
+  }
   await loadRecipeDetail();
 });
 
@@ -97,7 +106,7 @@ watch(
     <PageHeader :title="recipe.name" :subtitle="recipeSubtitle">
       <template #kicker>{{ t('pages.recipes.detailKicker') }}</template>
       <template #actions>
-        <RouterLink class="ui-button ui-button--primary ui-button--small" :to="`/recipes/${recipe.id}/edit`">
+        <RouterLink v-if="canUpdateRecipe" class="ui-button ui-button--primary ui-button--small" :to="`/recipes/${recipe.id}/edit`">
           <Icon :icon="iconEdit" class="ui-icon" aria-hidden="true" />
           {{ t('common.edit') }}
         </RouterLink>