Various UX improvements and bug fixes

- Fix mustChangePassword session flag for users with pw=NULL
- Add PrF (Private Führung) as new ArtFuehrung type
- Split datetime-local into separate date + TimePicker5 (5-min steps, auto-repeat)
- Responsive Beginn/Ende layout: stacked on mobile, inline on desktop
- Sort BEOs alphabetically by Kürzel in selector
- Title shows active kuppel; hide user display in header
- Selected BEOs show Kürzel only (name stays in dropdown)
- Session timeout reduced to 1 hour
- Add CLAUDE.md

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

components/LogbuchList.tsx

@@ -68,7 +68,7 @@ export default function LogbuchList({ kuppel, refreshKey, onEdit, limit = 20, co
               <th className={`${head} whitespace-nowrap`}>Beginn</th>
               <th className={`${head} whitespace-nowrap`}>Ende</th>
               <th className={head}>Art</th>
-              {!compact && <th className={`${head} text-center`}>Besucher</th>}
+              <th className={`${head} text-center`}>Besucher</th>
               <th className={head}>BEOs</th>
               <th className={head}>Objekte</th>
               {!compact && <th className={head}>Bemerkungen</th>}
@@ -81,7 +81,7 @@ export default function LogbuchList({ kuppel, refreshKey, onEdit, limit = 20, co
                 <td className={`${cell} whitespace-nowrap`}>{formatDateTime(e.Beginn, compact)}</td>
                 <td className={`${cell} whitespace-nowrap`}>{formatDateTime(e.Ende, compact)}</td>
                 <td className={cell}>{e.ArtFuehrung}</td>
-                {!compact && <td className={`${cell} text-center`}>{e.Besucher}</td>}
+                <td className={`${cell} text-center`}>{e.Besucher}</td>
                 <td className={cell}>{e.BEOs || '—'}</td>
                 <td className={cell}>{e.Objekte || '—'}</td>
                 {!compact && (