fix : add missing UI components, maintenance page, fix useRoute warning

- components/ui/SidebarLink.vue and AppTopNav.vue
- infra/prod/maintenance.html
- Remove useRoute() call in useApi onResponseError (fixes middleware warning)

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

frontend/components/ui/AppTopNav.vue

@@ -0,0 +1,48 @@
+<template>
+    <header class="border-b border-neutral-200 bg-primary-500 px-3 py-2 text-white sm:px-5 sm:py-2 max-h-[60px]">
+        <div class="flex h-full items-center justify-between">
+            <MalioButtonIcon
+                icon="mdi:menu"
+                aria-label="Menu"
+                variant="ghost"
+                icon-size="24"
+                button-class="lg:hidden text-white hover:bg-primary-600"
+                @click="ui.openMobileSidebar()"
+            />
+            <div class="hidden items-center gap-2 lg:flex">
+                <h1 class="text-lg font-bold tracking-tight">Coltura</h1>
+            </div>
+            <div class="ml-auto flex items-center gap-4 text-xl text-white sm:gap-8">
+                <div class="group relative flex gap-2 sm:gap-4">
+                    <Icon name="mdi:account-circle-outline" class="self-center cursor-pointer" size="36" />
+                    <p class="hidden self-center cursor-pointer sm:block">{{ user?.username }}</p>
+                    <div class="invisible absolute right-0 top-full z-50 mt-2 w-44 rounded-md border border-neutral-200 bg-white py-1 text-sm text-neutral-800 opacity-0 shadow-lg transition-all group-hover:visible group-hover:opacity-100">
+                        <button
+                            type="button"
+                            class="block w-full px-3 py-2 text-left hover:bg-neutral-100"
+                            @click="handleLogout"
+                        >
+                            Deconnexion
+                        </button>
+                    </div>
+                </div>
+            </div>
+        </div>
+    </header>
+</template>
+
+<script setup lang="ts">
+import type { UserData } from '~/services/dto/user-data'
+
+defineProps<{
+    user?: UserData | null
+}>()
+
+const auth = useAuthStore()
+const ui = useUiStore()
+
+async function handleLogout() {
+    await auth.logout()
+    await navigateTo('/login')
+}
+</script>