Fix semester context, attendance rosters, and billing workflows

- load global semester helpers consistently and use date-based semester defaults
- fix grading and daily attendance duplicate student/section rows
- keep attendance violations scoped to the current semester by default
- update invoice, refund, discount, payment, and financial aid flows
- add configuration cleanup migrations for duplicate calendar/semester keys
- refresh parent registration/report-card and print request handling
- update related models, services, views, cron notes, and test coverage

app/Commands/SendExamDraftDeadlineReminders.php

@@ -23,7 +23,7 @@ class SendExamDraftDeadlineReminders extends BaseCommand
 
         $configModel = new ConfigurationModel();
         $schoolYear = (string) ($configModel->getConfig('school_year') ?? '');
-        $semester = (string) ($configModel->getConfig('semester') ?? '');
+        $semester = (string) (getSemester() ?? '');
         $deadlineValue = trim((string) ($configModel->getConfig('exam_draft_deadline') ?? ''));
         if ($deadlineValue === '') {
             CLI::write('exam_draft_deadline is not configured.', 'yellow');