Add reset progress action for a candidate's quiz attempt, and modal-based candidate editing (#204)

* feat: add reset progress action for a candidate's quiz attempt

Admins previously had no way to let a candidate retake a quiz once
started. Adds a backoffice action that clears a candidate's given
answers and start timestamp for a quiz, closes #20.

* fix: wrap candidate progress reset in a transaction

Avoids leaving a candidate half-reset (answers deleted but started
still set) if the second flush fails. Addresses CodeRabbit review
comment on PR #204.

* feat: open candidate edit/add forms in modals with dirty-aware dismissal

Rename-candidate modal always blocked backdrop-click dismissal via a
hardcoded static backdrop; wire it into the existing bo--modal
controller so outside clicks/Escape only get blocked once the name
field has actually been edited. Also move "Add Candidate" from a
full-page navigation into the same turbo-frame modal pattern already
used for editing quiz questions, keeping the full-page form as a
fallback for non-JS/turbo requests.

* feat: show a hint for the candidates textarea and gate translations in CI

Add a help hint on the add-candidates form explaining one candidate per
line, and translate it plus a few strings from the earlier reset-progress
feature that had been missed. Also add a CI step that re-runs
translation:extract and fails the build if it produces uncommitted
changes, so untranslated/stale strings can't slip through review again.

* Just links

src/Controller/Backoffice/QuizController.php

@@ -25,6 +25,7 @@ use Tvdt\Entity\QuizCandidate;
 use Tvdt\Entity\Season;
 use Tvdt\Enum\FlashType;
 use Tvdt\Exception\ErrorClearingQuizException;
+use Tvdt\Repository\GivenAnswerRepository;
 use Tvdt\Repository\QuizCandidateRepository;
 use Tvdt\Repository\QuizRepository;
 use Tvdt\Security\Voter\SeasonVoter;
@@ -37,6 +38,7 @@ class QuizController extends AbstractController
         private readonly QuizRepository $quizRepository,
         private readonly TranslatorInterface $translator,
         private readonly QuizCandidateRepository $quizCandidateRepository,
+        private readonly GivenAnswerRepository $givenAnswerRepository,
         private readonly EntityManagerInterface $em,
     ) {}
 
@@ -397,6 +399,26 @@ class QuizController extends AbstractController
         return $this->redirectToRoute('tvdt_backoffice_quiz_candidates_tab', ['seasonCode' => $quiz->season->seasonCode, 'quiz' => $quiz->id]);
     }
 
+    #[IsCsrfTokenValid('reset_candidate_progress')]
+    #[IsGranted(SeasonVoter::EDIT, subject: 'quiz')]
+    #[Route(
+        '/backoffice/quiz/{quiz}/candidate/{candidate}/reset',
+        name: 'tvdt_backoffice_reset_candidate_progress',
+        requirements: ['quiz' => Requirement::UUID, 'candidate' => Requirement::UUID],
+        methods: ['POST'],
+    )]
+    public function resetCandidateProgress(Quiz $quiz, Candidate $candidate): RedirectResponse
+    {
+        $this->em->wrapInTransaction(function () use ($quiz, $candidate): void {
+            $this->givenAnswerRepository->deleteAllForCandidateInQuiz($quiz, $candidate);
+            $this->quizCandidateRepository->resetProgressForCandidate($quiz, $candidate);
+        });
+
+        $this->addFlash(FlashType::Success, $this->translator->trans('Candidate progress reset'));
+
+        return $this->redirectToRoute('tvdt_backoffice_quiz_candidates_tab', ['seasonCode' => $quiz->season->seasonCode, 'quiz' => $quiz->id]);
+    }
+
     /**
      * Pre-computes per-candidate data (quiz participation and given answer counts) to avoid nested loops in templates.
      *

src/Controller/Backoffice/SeasonController.php

@@ -129,6 +129,8 @@ class SeasonController extends AbstractController
     )]
     public function addCandidates(Season $season, Request $request): Response
     {
+        $isTurboFrame = $request->headers->has('Turbo-Frame');
+
         $form = $this->createForm(AddCandidatesFormType::class);
         $form->handleRequest($request);
 
@@ -140,10 +142,18 @@ class SeasonController extends AbstractController
 
             $this->em->flush();
 
-            return $this->redirectToRoute('tvdt_backoffice_season', ['seasonCode' => $season->seasonCode]);
+            if ($isTurboFrame) {
+                return new Response('<turbo-frame id="add-candidates-modal-frame"></turbo-frame>');
+            }
+
+            return $this->redirectToRoute('tvdt_backoffice_season_candidates', ['seasonCode' => $season->seasonCode]);
         }
 
-        return $this->render('backoffice/season_add_candidates.html.twig', ['form' => $form, 'season' => $season]);
+        $template = $isTurboFrame
+            ? 'backoffice/season/_add_candidates_frame.html.twig'
+            : 'backoffice/season_add_candidates.html.twig';
+
+        return $this->render($template, ['form' => $form, 'season' => $season]);
     }
 
     #[IsCsrfTokenValid('rename_candidate')]