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/Models/AttendanceTrackingModel.php

@@ -435,7 +435,7 @@ class AttendanceTrackingModel extends Model
         ?string $semester = null,
         ?string $schoolYear = null
     ): bool {
-        $semester   = $semester   ?? (new \App\Models\ConfigurationModel())->getConfig('semester');
+        $semester   = $semester   ?? getSemester();
         $schoolYear = $schoolYear ?? (new \App\Models\ConfigurationModel())->getConfig('school_year');
 
         $day  = substr($ymd, 0, 10);