fix(exam): gate Take Exam on confirmed attendance

The registrations table mirrored the server's old attendance deny-list —
ABSENT/WITHDRAWN/DISQUALIFIED — so the default REGISTERED fell through and
"Take exam" appeared before any invigilator had confirmed the candidate was
there. It is an allow-list now, PRESENT and LATE only, matching
ExamAttemptService.MAY_SIT.

A blocked candidate gets a reason rather than an empty cell: "Awaiting
attendance" with a tooltip while nobody has called the register, "Not sitting"
once attendance was taken and they are not. useExamAttempt does the same for
the direct-link path, and translates attendance_not_confirmed /
candidate_not_present instead of showing a raw error key on a Start button
that cannot work. The server refuses either way — this only makes the refusal
legible.

ScheduleExamModal no longer promises an admission number: scheduling makes a
sitting available, and the candidate registers for it themselves.

apps/portal/src/app/features/exam-attempt/hooks/useExamAttempt.ts

@@ -9,6 +9,9 @@ import type {
   SaveState,
 } from '../types/exam-attempt';
 
+/** Mirrors the server's allow-list (ExamAttemptService.MAY_SIT). */
+const MAY_SIT = ['PRESENT', 'LATE'];
+
 const ESSAY_DEBOUNCE_MS = 1500;
 
 type ViewState = 'loading' | 'not-started' | 'taking' | 'completed' | 'error';
@@ -83,6 +86,19 @@ export function useExamAttempt(examId: string | undefined) {
       setErrorMessage('You are not registered for this examination.');
       return;
     }
+    // Attendance gates the sitting, and the exam list already hides "Take
+    // exam" for these — this is the direct-link path. The server refuses
+    // either way (ExamAttemptService.MAY_SIT); this only makes the refusal
+    // legible instead of a raw error key on a Start button that never works.
+    if (!MAY_SIT.includes(registration.attendanceStatus)) {
+      setViewState('error');
+      setErrorMessage(
+        registration.attendanceStatus === 'REGISTERED'
+          ? 'An invigilator must confirm you are present before this exam opens.'
+          : 'Your attendance record does not permit sitting this examination.',
+      );
+      return;
+    }
     if (mineData) {
       seedFrom(mineData);
       return;
@@ -200,7 +216,14 @@ export function useExamAttempt(examId: string | undefined) {
       }).unwrap();
       seedFrom(result);
     } catch (error) {
-      notify.error(extractErrorMessage(error, 'Could not start the exam.'));
+      const key = extractErrorMessage(error, 'Could not start the exam.');
+      notify.error(
+        key === 'attendance_not_confirmed'
+          ? 'An invigilator must confirm you are present before this exam opens.'
+          : key === 'candidate_not_present'
+            ? 'Your attendance record does not permit sitting this examination.'
+            : key,
+      );
     }
   }, [examId, startTrigger, seedFrom]);
 

apps/portal/src/app/features/exams/pages/ExamsPage/columns.tsx

@@ -1,4 +1,4 @@
-import { Badge, Button, Text } from '@mantine/core';
+import { Badge, Button, Text, Tooltip } from '@mantine/core';
 import { IconFileText, IconGavel, IconPlayerPlay } from '@tabler/icons-react';
 import type { TFunction } from 'i18next';
 import type { AdvancedColumn } from '@ema-platform/ui';
@@ -20,7 +20,14 @@ const ATTENDANCE_COLOR: Record<AttendanceStatus, string> = {
   DISQUALIFIED: 'red',
 };
 
-const NOT_SITTING: AttendanceStatus[] = ['ABSENT', 'WITHDRAWN', 'DISQUALIFIED'];
+/**
+ * Attendance rulings that permit sitting the paper — an allow-list mirroring
+ * the server's (ExamAttemptService.MAY_SIT). The deny-list this replaced named
+ * only ABSENT/WITHDRAWN/DISQUALIFIED, so the default REGISTERED fell through
+ * and "Take exam" appeared before any invigilator had confirmed the candidate
+ * was there. LATE counts: a late arrival is present, just not on time.
+ */
+const MAY_SIT: AttendanceStatus[] = ['PRESENT', 'LATE'];
 
 export function registrationColumns(
   t: TFunction,
@@ -115,9 +122,26 @@ export function registrationColumns(
             </Badge>
           );
         }
-        const eligible =
-          exam?.status === 'ACTIVE' && !NOT_SITTING.includes(row.original.attendanceStatus);
-        if (!eligible || !deps.can([PORTAL_PERMISSIONS.APPLY_EXAM])) return null;
+        if (!deps.can([PORTAL_PERMISSIONS.APPLY_EXAM])) return null;
+        // Say why the exam is shut rather than rendering an empty cell: the
+        // candidate is waiting on an invigilator, and silence reads as a bug.
+        if (row.original.attendanceStatus === 'REGISTERED') {
+          return (
+            <Tooltip label={t('exams.columns.awaitingAttendanceHint')} multiline w={240}>
+              <Badge size="sm" variant="light" color="gray">
+                {t('exams.columns.awaitingAttendance')}
+              </Badge>
+            </Tooltip>
+          );
+        }
+        if (!MAY_SIT.includes(row.original.attendanceStatus)) {
+          return (
+            <Badge size="sm" variant="light" color="orange">
+              {t('exams.columns.notSitting')}
+            </Badge>
+          );
+        }
+        if (exam?.status !== 'ACTIVE') return null;
         return (
           <Button
             size="compact-xs"

apps/portal/src/app/i18n/locales/am.ts

@@ -978,6 +978,10 @@ export const am: Translations = {
       timeExpired: 'ጊዜው አልቋል',
       resumeExam: 'ፈተና ይቀጥሉ',
       takeExam: 'ፈተና ይውሰዱ',
+      awaitingAttendance: 'መገኘት በመጠባበቅ ላይ',
+      awaitingAttendanceHint:
+        'ፈተናው ከመከፈቱ በፊት ተቆጣጣሪ መገኘትዎን ማረጋገጥ አለበት።',
+      notSitting: 'አይፈተኑም',
       attendanceStatus: {
         REGISTERED: 'አልተጠራም',
         PRESENT: 'ተገኝቷል',

apps/portal/src/app/i18n/locales/en.ts

@@ -980,6 +980,10 @@ export const en = {
       timeExpired: 'Time expired',
       resumeExam: 'Resume exam',
       takeExam: 'Take exam',
+      awaitingAttendance: 'Awaiting attendance',
+      awaitingAttendanceHint:
+        'An invigilator must confirm you are present before the exam opens.',
+      notSitting: 'Not sitting',
       attendanceStatus: {
         REGISTERED: 'Not called',
         PRESENT: 'Present',