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

tests/app/Services/FeeCalculationServiceTest.php

@@ -0,0 +1,51 @@
+<?php
+
+namespace Tests\App\Services;
+
+use App\Services\FeeCalculationService;
+use CodeIgniter\Test\CIUnitTestCase;
+
+class FeeCalculationServiceTest extends CIUnitTestCase
+{
+    public function testRefundReversesLatestTuitionTierFirst(): void
+    {
+        $fees = $this->refundFeeStack(3, 2, 380.0, 280.0);
+
+        $this->assertSame([280.0], $fees);
+    }
+
+    public function testRefundKeepsReversingAdditionalFeesBeforeFirstStudentFee(): void
+    {
+        $fees = $this->refundFeeStack(3, 0, 380.0, 280.0);
+
+        $this->assertSame([280.0, 280.0, 380.0], $fees);
+    }
+
+    public function testSingleStudentWithdrawalRefundsFirstStudentFee(): void
+    {
+        $fees = $this->refundFeeStack(1, 0, 380.0, 280.0);
+
+        $this->assertSame([380.0], $fees);
+    }
+
+    /**
+     * @return array<int,float>
+     */
+    private function refundFeeStack(
+        int $originalStudentCount,
+        int $remainingStudentCount,
+        float $firstStudentFee,
+        float $additionalStudentFee
+    ): array {
+        $method = new \ReflectionMethod(FeeCalculationService::class, 'reverseTuitionRefundFeeStack');
+        $method->setAccessible(true);
+
+        return $method->invoke(
+            new FeeCalculationService(),
+            $originalStudentCount,
+            $remainingStudentCount,
+            $firstStudentFee,
+            $additionalStudentFee
+        );
+    }
+}