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/Controllers/View/ExamDraftController.php

@@ -65,7 +65,7 @@ class ExamDraftController extends BaseController
         $this->db = Database::connect();
 
         $this->schoolYear = (string) ($this->configModel->getConfig('school_year') ?? '');
-        $this->semester = (string) ($this->configModel->getConfig('semester') ?? '');
+        $this->semester = (string) (getSemester() ?? '');
         $this->hasFinalPdfColumn = $this->schemaHasColumn('exam_drafts', 'final_pdf_file');
         $this->hasIsLegacyColumn = $this->schemaHasColumn('exam_drafts', 'is_legacy');
         $this->hasAcceptanceTypeColumn = $this->schemaHasColumn('exam_drafts', 'acceptance_type');
@@ -882,7 +882,7 @@ class ExamDraftController extends BaseController
     private function syncAcademicContext(): void
     {
         $this->schoolYear = $this->currentSchoolYearName((string) ($this->configModel->getConfig('school_year') ?? ''));
-        $this->semester = (string) ($this->configModel->getConfig('semester') ?? '');
+        $this->semester = (string) (getSemester() ?? '');
     }
 
     private function applyExamDraftYearScope($query): void