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/PrintRequests.php

@@ -51,6 +51,7 @@ class PrintRequests extends BaseController
         $schoolYear = $context->yearName();
         
         $printRequestsQuery = $this->printRequestModel
+            ->distinct()
             ->select('print_requests.*, admins.firstname as admin_firstname, admins.lastname as admin_lastname')
             ->join('users as admins', 'admins.id = print_requests.admin_id', 'left')
             ->join('classSection cs', 'cs.class_section_id = print_requests.class_id', 'left')
@@ -67,6 +68,8 @@ class PrintRequests extends BaseController
         $data['sundays'] = $dateOptions['sundays'];
         $data['times'] = $dateOptions['times'];
         $data['isSchoolYearReadonly'] = $context->isReadonly();
+        $data['printRequestToken'] = $this->issuePrintRequestToken('print');
+        $data['copyRequestToken'] = $this->issuePrintRequestToken('copy');
 
         return view('print_requests/teacher_index', $data);
     }
@@ -77,6 +80,7 @@ class PrintRequests extends BaseController
         $schoolYear = $context->yearName();
 
         $printRequestsQuery = $this->printRequestModel
+            ->distinct()
             ->select('
                 print_requests.*,
                 u.firstname,
@@ -125,6 +129,10 @@ class PrintRequests extends BaseController
             return redirect()->back()->withInput()->with('errors', $this->validator->getErrors());
         }
 
+        if (! $this->consumePrintRequestToken('print')) {
+            return redirect()->to('teacher/print-requests')->with('error', 'This print request was already submitted. Please refresh the page before submitting another request.');
+        }
+
         $teacher_id = session()->get('user_id');
 
         $file = $this->request->getFile('file');
@@ -346,6 +354,10 @@ class PrintRequests extends BaseController
             return redirect()->back()->withInput()->with('errors', $this->validator->getErrors());
         }
 
+        if (! $this->consumePrintRequestToken('copy')) {
+            return redirect()->to('teacher/print-requests')->with('error', 'This copy request was already submitted. Please refresh the page before submitting another request.');
+        }
+
         $teacher_id = session()->get('user_id');
 
         $data = [
@@ -402,6 +414,54 @@ class PrintRequests extends BaseController
         ];
     }
 
+    private function issuePrintRequestToken(string $type): string
+    {
+        $key = $this->printRequestTokenSessionKey($type);
+        $tokens = session()->get($key);
+
+        if (! is_array($tokens)) {
+            $tokens = [];
+        }
+
+        $token = bin2hex(random_bytes(16));
+        $tokens[$token] = time();
+
+        if (count($tokens) > 20) {
+            asort($tokens);
+            $tokens = array_slice($tokens, -20, null, true);
+        }
+
+        session()->set($key, $tokens);
+
+        return $token;
+    }
+
+    private function consumePrintRequestToken(string $type): bool
+    {
+        $token = (string) $this->request->getPost('request_token');
+
+        if ($token === '') {
+            return false;
+        }
+
+        $key = $this->printRequestTokenSessionKey($type);
+        $tokens = session()->get($key);
+
+        if (! is_array($tokens) || ! array_key_exists($token, $tokens)) {
+            return false;
+        }
+
+        unset($tokens[$token]);
+        session()->set($key, $tokens);
+
+        return true;
+    }
+
+    private function printRequestTokenSessionKey(string $type): string
+    {
+        return 'print_request_' . $type . '_tokens';
+    }
+
     private function applyPrintRequestSchoolYearScope($query, string $schoolYear): void
     {
         if ($schoolYear === '') {
@@ -620,7 +680,7 @@ class PrintRequests extends BaseController
             'action_url' => $isCopyRequest ? '' : $actionUrl,
             'scheduled_at' => utc_now(),
             'school_year' => $this->configModel->getConfig('school_year'),
-            'semester' => $this->configModel->getConfig('semester'),
+            'semester' => getSemester(),
         ];
 
         $notificationFields = $db->getFieldNames('notifications');