feat(frontend): layout header + drawer + router (9 routes)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/stores/plantings.js

@@ -0,0 +1,22 @@
+import { defineStore } from 'pinia';
+import { ref } from 'vue';
+import { plantingsApi } from '@/api/plantings';
+export const usePlantingsStore = defineStore('plantings', () => {
+    const plantings = ref([]);
+    const loading = ref(false);
+    async function fetchAll() {
+        loading.value = true;
+        plantings.value = await plantingsApi.list();
+        loading.value = false;
+    }
+    async function create(p) {
+        const created = await plantingsApi.create(p);
+        plantings.value.push(created);
+        return created;
+    }
+    async function remove(id) {
+        await plantingsApi.delete(id);
+        plantings.value = plantings.value.filter(p => p.id !== id);
+    }
+    return { plantings, loading, fetchAll, create, remove };
+});