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/ConfigurationModel.php

@@ -86,12 +86,9 @@ class ConfigurationModel extends Model
 
         if ($key === 'semester') {
             try {
-                $semester = (new \App\Services\SemesterRangeService($this))->getSemesterForDate();
-                if ($semester !== '') {
-                    return $semester;
-                }
+                return (new \App\Services\SemesterRangeService($this))->getSemesterForDate() ?: 'Fall';
             } catch (\Throwable $e) {
-                // ignore and fall back
+                return 'Fall';
             }
         }