Add announcement editing and reliable per-recipient mail delivery

src/app/dashboard/admin/news/news-form.tsx

@@ -1,6 +1,6 @@
 "use client";
 
-import { useState, useTransition } from "react";
+import { useRef, useState, useTransition } from "react";
 import { Loader2, Send, UploadCloud } from "lucide-react";
 import { toast } from "sonner";
 
@@ -20,6 +20,7 @@ import { Textarea } from "@/components/ui/textarea";
 import { MarkdownContent } from "@/components/markdown-content";
 
 export function NewsForm() {
+  const formRef = useRef<HTMLFormElement>(null);
   const [isPending, startTransition] = useTransition();
   const [sendEmail, setSendEmail] = useState(false);
   const [content, setContent] = useState("");
@@ -30,27 +31,43 @@ export function NewsForm() {
         formData.set("sendEmail", "on");
       }
 
-      const result = await createAnnouncement(formData);
-      if (result.error) {
-        toast.error(result.error);
-        return;
-      }
+      try {
+        const result = await createAnnouncement(formData);
+        if (result.error) {
+          toast.error(result.error);
+          return;
+        }
 
-      if (result.warning) {
-        toast.warning(result.warning);
-      } else {
-        toast.success("Ankündigung veröffentlicht.");
+        if (result.warning) {
+          toast.warning(result.warning);
+        } else {
+          toast.success(
+            sendEmail
+              ? "Ankündigung veröffentlicht. E-Mails sind zum Versand vorgemerkt."
+              : "Ankündigung veröffentlicht.",
+          );
+        }
+        formRef.current?.reset();
+        setContent("");
+        setSendEmail(false);
+      } catch {
+        toast.error(
+          "Ankündigung konnte nicht veröffentlicht werden. Bitte versuche es erneut.",
+        );
       }
     });
   }
 
   return (
-    <form action={handleSubmit} className="grid gap-5">
+    <form ref={formRef} action={handleSubmit} className="grid gap-5">
       <div className="grid gap-2">
         <Label htmlFor="news-title">Titel</Label>
         <Input
           id="news-title"
           name="title"
+          minLength={3}
+          maxLength={160}
+          disabled={isPending}
           placeholder="Sommerfest: Aufbau und Mitbringliste"
           required
         />
@@ -62,6 +79,9 @@ export function NewsForm() {
           id="news-content"
           name="content"
           rows={10}
+          minLength={3}
+          maxLength={20_000}
+          disabled={isPending}
           value={content}
           onChange={(event) => setContent(event.target.value)}
           placeholder={