feat(ui): use modal dialogs for entity creation and editing

Introduce reusable Modal component for forms
Update router to preserve scroll position when toggling modals
Refactor admin and entity views to render editors as overlays

frontend/src/views/HabitatList.vue

@@ -1,17 +1,21 @@
 <script setup lang="ts">
-import { onMounted, ref } from 'vue';
+import { computed, onMounted, ref } from 'vue';
 import { useI18n } from 'vue-i18n';
+import { useRoute } from 'vue-router';
 import EditMeta from '../components/EditMeta.vue';
 import EntityChips from '../components/EntityChips.vue';
 import EntityCard from '../components/EntityCard.vue';
 import PageHeader from '../components/PageHeader.vue';
 import Skeleton from '../components/Skeleton.vue';
 import { api, type Habitat } from '../services/api';
+import HabitatEdit from './HabitatEdit.vue';
 
 const habitats = ref<Habitat[]>([]);
+const route = useRoute();
 const { t } = useI18n();
 const loading = ref(true);
 const skeletonCardCount = 6;
+const showEditor = computed(() => route.name === 'habitat-new');
 
 onMounted(async () => {
   habitats.value = await api.habitats();
@@ -50,5 +54,7 @@ onMounted(async () => {
         <EntityChips :items="item.pokemon ?? []" />
       </EntityCard>
     </div>
+
+    <HabitatEdit v-if="showEditor" />
   </section>
 </template>