Add getStudentName display-name util (#235)

Composes a student's display name from firstName + lastName, handling
trimming and single-name fallback once instead of per call site.

Closes #234

Author: rappm

src/lib/getStudentName.ts

@@ -0,0 +1,5 @@
+export const getStudentName = (student: { firstName?: string; lastName?: string }): string =>
+  [student.firstName, student.lastName]
+    .map((part) => part?.trim())
+    .filter(Boolean)
+    .join(' ')

src/lib/index.ts

@@ -2,6 +2,7 @@ export * from './utils'
 export * from './formatFileSize'
 export * from './getCountries'
 export * from './getGravatarUrl'
+export * from './getStudentName'
 export * from './getStatusBadge'
 export * from './getStatusColor'
 export * from './openFileDownload'