Summer cleanup: XLSX export, WIDM-style quiz UI, CSS fixes (#162)

* Add CLAUDE.md, replace Makefile with Justfile, remove .junie

- Add CLAUDE.md with project overview, commands, architecture, and domain entity docs
- Remove Makefile in favour of the existing Justfile
- Remove .junie/AGENTS.md (knowledge transferred to CLAUDE.md)
- Update .gitignore: drop .junie/ entries, add .claude/settings.local.json
- Minor doc fixes in config/reference.php (typo, type correction)

* Clean up templates and CSS

- season.html.twig: remove dead empty column, drop redundant flex-row
- tab_overview.html.twig: extract Twig macro for confirm modals, fix duplicate aria-labelledby IDs
- tab_result.html.twig: remove dead comment, replace inline widths with CSS classes, simplify nested row/col forms to d-flex gap-1
- backoffice.scss: add col-result-xs/sm/md column width classes
- quiz.scss: replace broken display:grid + justify-self:center with flexbox centering

* Implement quizToXlsx() export and add export button

- QuizSpreadsheetService: implement quizToXlsx() as the inverse of
  fillQuizFromArray() — writes quiz questions and answers to XLSX using
  the same column layout as the import template
- BackofficeController: add exportQuiz() action at GET /backoffice/quiz/{quiz}/export
- tab_overview.html.twig: add Export to XLSX button in Quick actions

* Add unit tests for QuizSpreadsheetService

7 tests covering generateTemplate(), quizToXlsx(), and xlsxToQuiz():
- valid XLSX output and MIME type
- template without example reimports as empty
- template example data survives a reimport
- round-trip (export → reimport) preserves questions, answers, and correct flags
- empty quiz exports and reimports cleanly
- invalid MIME type throws InvalidArgumentException
- question with no answers throws SpreadsheetDataException with error list

* Fix quiz page vertical centering regression

The CSS cleanup broke vertical centering: flex on body causes main to
stretch full-width; place-items:center on a grid body only centers
items within their auto-sized track (not the track within body).

Fix: move background/color to html (full-viewport grid that centers
body), give body height:100% + display:grid + align-content:center
(centers the content track within full-height body) + justify-self:center
(shrink-wraps body width). Matches production behavior exactly.

* Improve quiz page layouts: WIDM-style answers and responsive centering

- Add green square answer buttons styled after the TV show
- Two-column answer grid for 6+ answers, single column on mobile
- fit-content centering for question pages so block matches question width
- Narrow fixed-width centering for form pages (enter name, select season)

* Use HeaderUtils::makeDisposition() for safe Content-Disposition filename

* Fix quizToXlsx to support unlimited answers and add header count tests

- Replace hardcoded 6-column arrays with dynamic Coordinate arithmetic
- Write data rows first to determine max answer count, write headers last
- Replace try/catch ErrorException in fillQuizFromArray with array_key_exists
- Add data-provider test covering 2, 6, 7, and 10 answers
- Add cross-question max-header and 7-answer round-trip tests

* Fix Sass healthcheck

* Improve quiz layout: add fixed topbar, include navigation, and clean up unused elements

- Add `.quiz-topbar` with fixed positioning and spacing in `quiz.scss`
- Update `base.html.twig` to include `quiz/nav.html.twig` in a new `nav` block
- Remove unused "Manage Quiz" button from `select_season.html.twig`

* Refactor generateTemplate to reuse quizToXlsx and add second example question

- generateTemplate now builds an in-memory Quiz entity and delegates to
  quizToXlsx, eliminating duplicate spreadsheet-building logic
- Adds a second example question "Wie is de mol?" with 10 Dutch names
  (5 male, 5 female) to better illustrate the import format
- Updates tests to assert both example questions and adds a test for the
  blank-row halt behaviour in fillQuizFromArray (achieving 100% coverage)

* Move PHPUnit cache to /tmp to avoid writing into the mounted volume

* Update src/Service/QuizSpreadsheetService.php

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

---------

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

src/Service/QuizSpreadsheetService.php

@@ -4,6 +4,7 @@ declare(strict_types=1);
 
 namespace Tvdt\Service;
 
+use PhpOffice\PhpSpreadsheet\Cell\Coordinate;
 use PhpOffice\PhpSpreadsheet\Reader;
 use PhpOffice\PhpSpreadsheet\Spreadsheet;
 use PhpOffice\PhpSpreadsheet\Writer;
@@ -17,39 +18,40 @@ class QuizSpreadsheetService
 {
     public function generateTemplate(bool $fillExample = true): \Closure
     {
-        $spreadsheet = new Spreadsheet();
-
-        $sheet = $spreadsheet->getActiveSheet();
-
-        $sheet->getStyle('1:1')->getFont()->setBold(true);
-
-        $sheet->setCellValue('A1', 'Question');
-        $sheet->getColumnDimension('A')->setWidth(30);
-        $sheet->getStyle('A:A')->getAlignment()->setWrapText(true);
-
-        $counter = 1;
-        foreach (range('B', 'L', 2) as $column) {
-            $sheet->setCellValue($column.'1', 'Answer '.$counter++);
-            $sheet->getColumnDimension($column)->setWidth(30);
-            $sheet->getStyle($column.':'.$column)->getAlignment()->setWrapText(true);
-        }
-
-        foreach (range('C', 'M', 2) as $column) {
-            $sheet->setCellValue($column.'1', 'Correct');
-            $sheet->getColumnDimension($column)->setAutoSize(true);
-        }
+        $quiz = new Quiz();
 
         if ($fillExample) {
-            $sheet->setCellValue('B2', 'Man');
-            $sheet->setCellValue('C2', true);
+            $geslacht = new Question();
+            $geslacht->question = 'Is de mol een man of een vrouw?';
+            $geslacht->ordering = 1;
+            $geslacht->addAnswer(new Answer('Man', true));
+            $geslacht->addAnswer(new Answer('Vrouw'));
+            $quiz->addQuestion($geslacht);
 
-            $sheet->setCellValue('D2', 'Vrouw');
-            $sheet->setCellValue('E2', false);
+            $identiteit = new Question();
+            $identiteit->question = 'Wie is de mol?';
+            $identiteit->ordering = 2;
+            foreach ([
+                ['Emma', false],
+                ['Jan', false],
+                ['Sara', false],
+                ['Piet', false],
+                ['Lisa', true],
+                ['Kees', false],
+                ['Anna', false],
+                ['Henk', false],
+                ['Nina', false],
+                ['Joost', false],
+            ] as $i => [$name, $correct]) {
+                $answer = new Answer($name, $correct);
+                $answer->ordering = $i + 1;
+                $identiteit->addAnswer($answer);
+            }
 
-            $sheet->setCellValue('A2', 'Is de mol een man of een vrouw?');
+            $quiz->addQuestion($identiteit);
         }
 
-        return $this->toXlsx($spreadsheet);
+        return $this->quizToXlsx($quiz);
     }
 
     /** @throws SpreadsheetDataException */
@@ -94,24 +96,16 @@ class QuizSpreadsheetService
             $answerCounter = 1;
             $arrCounter = 1;
 
-            while (true) {
-                try {
-                    if (null === $questionArr[$arrCounter]) {
-                        if (1 === $answerCounter) {
-                            $errors[] = \sprintf('Question %d has no answers', $answerCounter);
-                        }
-
-                        break;
-                    }
-                } catch (\ErrorException) {
-                    break;
-                }
-
+            while (\array_key_exists($arrCounter, $questionArr) && null !== $questionArr[$arrCounter]) {
                 $answer = new Answer((string) $questionArr[$arrCounter++], (bool) $questionArr[$arrCounter++]);
                 $answer->ordering = $answerCounter++;
                 $question->addAnswer($answer);
             }
 
+            if (1 === $answerCounter) {
+                $errors[] = \sprintf('Question %d has no answers', $question->ordering);
+            }
+
             $quiz->addQuestion($question);
         }
 
@@ -120,9 +114,47 @@ class QuizSpreadsheetService
         }
     }
 
-    public function quizToXlsx(Quiz $quiz): void
+    public function quizToXlsx(Quiz $quiz): \Closure
     {
-        throw new \Exception('Not implemented');
+        $spreadsheet = new Spreadsheet();
+        $sheet = $spreadsheet->getActiveSheet();
+
+        // Write data rows first so we know the maximum answer count.
+        $maxAnswers = 0;
+        $row = 2;
+        foreach ($quiz->questions as $question) {
+            $sheet->setCellValue('A'.$row, $question->question);
+
+            $col = 0;
+            foreach ($question->answers as $answer) {
+                $sheet->setCellValue(Coordinate::stringFromColumnIndex(2 + 2 * $col).$row, $answer->text);
+                $sheet->setCellValue(Coordinate::stringFromColumnIndex(3 + 2 * $col).$row, $answer->isRightAnswer);
+                ++$col;
+            }
+
+            $maxAnswers = max($maxAnswers, $col);
+            ++$row;
+        }
+
+        // Write headers last, sized to the widest question.
+        $sheet->getStyle('1:1')->getFont()->setBold(true);
+        $sheet->setCellValue('A1', 'Question');
+        $sheet->getColumnDimension('A')->setWidth(30);
+        $sheet->getStyle('A:A')->getAlignment()->setWrapText(true);
+
+        for ($i = 0; $i < $maxAnswers; ++$i) {
+            $answerCol = Coordinate::stringFromColumnIndex(2 + 2 * $i);
+            $correctCol = Coordinate::stringFromColumnIndex(3 + 2 * $i);
+
+            $sheet->setCellValue($answerCol.'1', 'Answer '.($i + 1));
+            $sheet->getColumnDimension($answerCol)->setWidth(30);
+            $sheet->getStyle($answerCol.':'.$answerCol)->getAlignment()->setWrapText(true);
+
+            $sheet->setCellValue($correctCol.'1', 'Correct');
+            $sheet->getColumnDimension($correctCol)->setAutoSize(true);
+        }
+
+        return $this->toXlsx($spreadsheet);
     }
 
     private function toXlsx(Spreadsheet $spreadsheet): \Closure