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/Views/partials/navbar.php

@@ -277,7 +277,7 @@ switch ($role) {
         } catch (\Throwable $e) {
             $year = $sess->get('school_year') ?? $configModel->getConfig('school_year');
         }
-        $semester = $sess->get('semester') ?? $configModel->getConfig('semester');
+        $semester = $sess->get('semester') ?? getSemester();
         $activeEventCount = count($eventModel->getActiveEvents($year, $semester) ?? []);
     }
 ?>