allow vorgangPIN to be changed on Vorgang page

includes:
- UI and backend logic
- adjustment to `NameItemEditor` to disallow deletion

src/routes/(token-based)/list/[vorgang]/+page.svelte

@@ -190,6 +190,34 @@
 		}
 	}
 
+	async function savePIN(newVorgangPIN: string, oldVorgangPIN: string) {
+		open = true;
+		inProgress = true;
+		isError = false;
+		try {
+			const res = await fetch(API_ROUTES.VORGANG(vorgangToken), {
+				method: 'PUT',
+				headers: {
+					'Content-Type': 'application/json'
+				},
+				body: JSON.stringify({ vorgangToken, oldVorgangPIN, newVorgangPIN,
+										changePIN: true})
+			});
+
+			if (!res.ok) {
+				throw new Error('Fehler beim Speichern');
+			}
+			await invalidateAll();
+			crimesList = data.crimesList;
+			open = false;
+		} catch (err) {
+			console.error('⚠️ Netzwerkfehler beim Speichern', err);
+			isError = true;
+		} finally {
+			inProgress = false;
+		}
+	}
+
 	async function handleDelete(tatort: string) {
 		open = true;
 		inProgress = true;
@@ -251,7 +279,13 @@ Mit freundlichen Grüßen,
 			<h1 class="text-xl">{vorgangName}</h1>
 
 			{#if admin}
-				Zugangs-PIN: {vorgangPIN}
+				Zugangs-PIN:
+				<NameItemEditor
+				list={[]}
+				currentName={vorgangPIN}
+				onSave={savePIN}
+				onDelete={null}
+				/>
 				<a class="pt-2 pb-6" href={constructMailToLink()}
 					><Button disabled={isEmptyList}>Share Link</Button></a
 				>

src/routes/api/list/[vorgang]/+server.ts

@@ -4,7 +4,7 @@ import {
 	deleteVorgangByToken,
 	getCrimesListByToken,
 	vorgangNameExists,
-	renameVorgangByToken
+	updateVorgangAttrByToken
 } from '$lib/server/vorgangService';
 
 export async function DELETE({ params }) {
@@ -59,14 +59,26 @@ export async function GET({ params }) {
 	}
 }
 
-// rename vorgang
+// change Vorgang properties
 export async function PUT({ request }) {
 	const data = await request.json();
 	
 	const vorgangToken = data['vorgangToken'];
-	const newVorgangName = data['newName'];
+
+	const changePIN = data['changePIN'];
+
+	let attrChanged;
+	let newValue;
 	
-	const res = renameVorgangByToken(vorgangToken, newVorgangName);
+	if (changePIN) {
+		attrChanged = 'pin';
+		newValue = data['newVorgangPIN']
+	} else {
+		attrChanged = 'name';
+		newValue = data['newName']
+	}
+
+	const res = updateVorgangAttrByToken(vorgangToken, newValue, attrChanged);
 	
 	if (!res) {
 		return json({ msg: 'Fehler beim Umbenennen' }, { status: 400 });