Umbenennung. Logbuch -> Führungsbuch

app/MainClient.tsx

@@ -55,7 +55,7 @@ export default function MainClient({ kuerzel, beoId, beoName, role }: Props) {
         <div className="flex justify-between items-start sm:items-center mb-3 gap-2 print:hidden">
           <h1 className="text-xl sm:text-2xl font-bold leading-tight">
             <span className="hidden sm:inline">Sternwarte-Welzheim &nbsp; </span>
-            Logbuch für {activeKuppel}-Kuppel
+            Führungsbuch für {activeKuppel}-Kuppel
           </h1>
           <div className="flex items-center gap-2 shrink-0">
             {role?.includes('admin') && (
@@ -161,7 +161,7 @@ export default function MainClient({ kuerzel, beoId, beoName, role }: Props) {
         {activeTab === 'liste' && (
           <div className="border-2 border-gray-400 rounded-xl bg-white p-3 print:border-0 print:rounded-none print:p-0">
             <div className="hidden print:block mb-4">
-              <div className="text-lg font-bold">Sternwarte Welzheim — Logbuch {activeKuppel}-Kuppel</div>
+              <div className="text-lg font-bold">Sternwarte Welzheim — Führungsbuch {activeKuppel}-Kuppel</div>
               <div className="text-sm text-gray-500">Ausdruck vom {new Date().toLocaleDateString('de-DE')}</div>
             </div>
             <LogbuchList