added checkmark upon task completion for individual users

frontend/src/pages/ChallengeListPage.jsx

@@ -16,12 +16,17 @@ const TYPE_LABEL = {
 
 export default function ChallengeListPage() {
   const [challenges, setChallenges] = useState([])
+  const [passedIds, setPassedIds] = useState(new Set())
   const [error, setError] = useState(null)
 
   useEffect(() => {
-    api.get('/challenges')
-      .then(res => setChallenges(res.data))
-      .catch(() => setError('Failed to load challenges.'))
+    Promise.all([
+      api.get('/challenges'),
+      api.get('/submissions/me/passed'),
+    ]).then(([challengesRes, passedRes]) => {
+      setChallenges(challengesRes.data)
+      setPassedIds(new Set(passedRes.data))
+    }).catch(() => setError('Failed to load challenges.'))
   }, [])
 
   return (
@@ -37,6 +42,7 @@ export default function ChallengeListPage() {
         <table style={{ width: '100%', borderCollapse: 'collapse' }}>
           <thead>
             <tr style={{ borderBottom: '1px solid #2d3748', color: '#718096', fontSize: 13, textAlign: 'left' }}>
+              <th style={{ padding: '8px 12px', width: 32 }}></th>
               <th style={{ padding: '8px 12px' }}>#</th>
               <th style={{ padding: '8px 12px' }}>Title</th>
               <th style={{ padding: '8px 12px' }}>Type</th>
@@ -49,6 +55,9 @@ export default function ChallengeListPage() {
                 key={c.id}
                 style={{ borderBottom: '1px solid #1a202c' }}
               >
+                <td style={{ padding: '12px 12px', fontSize: 14, color: '#68d391' }}>
+                  {passedIds.has(c.id) ? '✓' : ''}
+                </td>
                 <td style={{ padding: '12px 12px', color: '#718096', fontSize: 14 }}>{i + 1}</td>
                 <td style={{ padding: '12px 12px' }}>
                   <Link to={`/challenges/${c.id}`} style={{ fontWeight: 500 }}>

src/main/java/no/hvl/schemalab/controller/SubmissionController.java

@@ -58,4 +58,16 @@ public List<Submission> mySubmissions() {
                 .orElseThrow(() -> new RuntimeException("User not found"));
         return submissionRepository.findByUser(user);
     }
+
+    @GetMapping("/me/passed")
+    public List<Long> passedChallengeIds() {
+        String username = SecurityContextHolder.getContext().getAuthentication().getName();
+        AppUser user = appUserRepository.findByUsername(username)
+                .orElseThrow(() -> new RuntimeException("User not found"));
+        return submissionRepository.findByUserAndStatus(user, "PASS")
+                .stream()
+                .map(s -> s.getChallenge().getId())
+                .distinct()
+                .toList();
+    }
 }

src/main/java/no/hvl/schemalab/repository/SubmissionRepository.java

@@ -8,4 +8,5 @@
 
 public interface SubmissionRepository extends JpaRepository<Submission, Long> {
     List<Submission> findByUser(AppUser user);
+    List<Submission> findByUserAndStatus(AppUser user, String status);
 }