feat: CSV-Import/-Export für Gerichte/Allergene/Zusatzstoffe, RSS-Fix für mehrere Essenszeiten

CSV-Import/-Export (Gerichte, Allergene, Zusatzstoffe): neue Export-/
Import-Routen unter app/api/*/export und */import, hand-geschriebener
CSV-Parser/-Serializer (lib/csv.ts, keine neue Abhängigkeit), Upsert
über Kürzel (Allergene/Zusatzstoffe) bzw. exakten Namen (Gerichte,
mit Ambiguitäts-Check bei Namensdopplung). UI-Buttons in DishManager
und CodeListManager.

RSS-Feed: <content:encoded> zusätzlich zu <description> ausgeben,
da mehrere Feed-Reader description als kürzbare Vorschau behandeln
und dadurch bei mehreren Essenszeiten pro Tag nur die erste zeigten.

Version 1.7.0.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

components/DishManager.tsx

@@ -40,6 +40,8 @@ export default function DishManager({
   const [additives, setAdditives] = useState<CodeItem[]>([]);
   const [form, setForm] = useState<DishForm | null>(null);
   const [error, setError] = useState<string | null>(null);
+  const [notice, setNotice] = useState<string | null>(null);
+  const [ioBusy, setIoBusy] = useState(false);
   const [loading, setLoading] = useState(true);
   const [selected, setSelected] = useState<Set<string>>(new Set());
   const [bulkBusy, setBulkBusy] = useState(false);
@@ -219,6 +221,58 @@ export default function DishManager({
     }
   }
 
+  async function exportDishes() {
+    setError(null);
+    setNotice(null);
+    const res = await fetch("/api/dishes/export");
+    if (!res.ok) {
+      setError(formatMessage(dict.dishManager.exportError, { message: String(res.status) }));
+      return;
+    }
+    const blob = await res.blob();
+    const url = URL.createObjectURL(blob);
+    const a = document.createElement("a");
+    a.href = url;
+    a.download = "gerichte.csv";
+    a.click();
+    URL.revokeObjectURL(url);
+  }
+
+  async function importDishes(e: React.ChangeEvent<HTMLInputElement>) {
+    const file = e.target.files?.[0];
+    e.target.value = "";
+    if (!file) return;
+    setError(null);
+    setNotice(null);
+    setIoBusy(true);
+    const fd = new FormData();
+    fd.append("file", file);
+    const res = await fetch("/api/dishes/import", { method: "POST", body: fd });
+    setIoBusy(false);
+    if (!res.ok) {
+      setError(formatMessage(dict.dishManager.importError, { message: String(res.status) }));
+      return;
+    }
+    const data = (await res.json()) as {
+      created: number;
+      updated: number;
+      skipped: { row: number; reason: string }[];
+    };
+    let msg = formatMessage(dict.dishManager.importSuccess, {
+      created: data.created,
+      updated: data.updated,
+    });
+    if (data.skipped.length > 0) {
+      const reasons = data.skipped
+        .map((s) => formatMessage(dict.dishManager.importSkippedRow, s))
+        .join("; ");
+      msg +=
+        " " + formatMessage(dict.dishManager.importSkipped, { count: data.skipped.length, reasons });
+    }
+    setNotice(msg);
+    await load();
+  }
+
   const allSelected =
     visible.length > 0 && visible.every((d) => selected.has(d.id));
 
@@ -228,6 +282,19 @@ export default function DishManager({
         <h1 className="text-xl font-bold text-[var(--c-primary)] mr-auto">
           {dict.dishManager.title}
         </h1>
+        <button type="button" className="btn btn-neutral" onClick={exportDishes}>
+          {dict.dishManager.exportButton}
+        </button>
+        <label className="btn btn-neutral cursor-pointer">
+          {dict.dishManager.importButton}
+          <input
+            type="file"
+            accept=".csv,text/csv"
+            className="hidden"
+            onChange={importDishes}
+            disabled={ioBusy}
+          />
+        </label>
         <button
           type="button"
           className="btn btn-add"
@@ -245,6 +312,7 @@ export default function DishManager({
           {error}
         </p>
       )}
+      {notice && <p className="mb-3 text-sm text-green-700">{notice}</p>}
 
       {form && (
         <form onSubmit={save} className="card mb-4 space-y-4">