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/RefundModel.php

@@ -2,8 +2,10 @@
 
 namespace App\Models;
 
+use CodeIgniter\Database\ConnectionInterface;
 use CodeIgniter\Model;
 use App\Models\Concerns\SchoolYearAutoFillTrait;
+use CodeIgniter\Validation\ValidationInterface;
 
 class RefundModel extends Model
 {
@@ -50,6 +52,39 @@ class RefundModel extends Model
     protected $createdField  = 'created_at';
     protected $updatedField  = 'updated_at';
 
+    private array $refundColumns = [];
+
+    public function __construct(?ConnectionInterface $db = null, ?ValidationInterface $validation = null)
+    {
+        parent::__construct($db, $validation);
+
+        $this->refundColumns = $this->getTableColumns($this->table);
+        $this->allowedFields = array_values(array_filter(
+            $this->allowedFields,
+            fn (string $field): bool => in_array($field, $this->refundColumns, true)
+        ));
+
+        foreach (array_keys($this->validationRules) as $field) {
+            if (!in_array($field, $this->allowedFields, true)) {
+                unset($this->validationRules[$field]);
+            }
+        }
+    }
+
+    private function getTableColumns(string $table): array
+    {
+        try {
+            return $this->db->getFieldNames($table);
+        } catch (\Throwable $e) {
+            log_message('error', '[RefundModel] Could not read table columns for {table}: {error}', [
+                'table' => $table,
+                'error' => $e->getMessage(),
+            ]);
+
+            return [];
+        }
+    }
+
     /**
      * Get total approved refund for a parent in a specific school year.
      *