feat: review open answers in the admin and pick a grader per quiz

- Do oceny admin screen (golem15.quizzes.reviews) over the open answers,
  with a read-only context partial, score and comment virtual fields saved
  through SetScore, confirm and regrade record actions, bulk confirm
- open question type, rubric and max_length in the question form; grader
  dropdown on the quiz form from the grader registry
- Review model with quiz, status and student filters

models/questions/fields.yaml

@@ -15,6 +15,7 @@ fields:
             single: golem15.quizzes::lang.questions.type_single
             multiple: golem15.quizzes::lang.questions.type_multiple
             self_check: golem15.quizzes::lang.questions.type_self_check
+            open: golem15.quizzes::lang.questions.type_open
     text:
         label: golem15.quizzes::lang.questions.text
         type: textarea
@@ -35,6 +36,16 @@ fields:
         type: textarea
         size: small
         comment: golem15.quizzes::lang.questions.answer_text_comment
+    rubric:
+        label: golem15.quizzes::lang.questions.rubric
+        type: textarea
+        size: small
+        comment: golem15.quizzes::lang.questions.rubric_comment
+    max_length:
+        label: golem15.quizzes::lang.questions.max_length
+        type: number
+        span: left
+        comment: golem15.quizzes::lang.questions.max_length_comment
     explanation:
         label: golem15.quizzes::lang.questions.explanation
         type: textarea