fix: attendance admin — add user_name to records, fix Czech diacritics in table headers

- listAttendance() now maps users.first_name + last_name to user_name
- Fixed escaped Unicode in table headers (Zaměstnanec, Příchod, Poznámka)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/services/attendance.service.ts

@@ -725,8 +725,10 @@ export async function listAttendance(params: ListAttendanceParams) {
       ...l,
       project_name: projectNameMap.get(l.project_id) || `Projekt #${l.project_id}`,
     }));
+    const u = rec.users;
     return {
       ...rec,
+      user_name: u ? `${u.first_name} ${u.last_name}`.trim() : '',
       project_name: rec.project_id ? (projectNameMap.get(rec.project_id) || null) : null,
       project_logs: logs,
     };