feat: add new question types and components for fill-in-the-blanks, true/false, code submission, dropdown completion, numeric range, dictation, grammar correction, and flashcards

- Updated QuestionRenderer to support new question types.
- Added FillInTheBlanks, TrueFalse, CodeSubmission, DropdownCompletion, NumericRange, Dictation, GrammarCorrection, and Flashcard components.
- Enhanced grading logic to handle new question types.
- Updated translations for new question types in English and Dutch.
- Added CSS styles for new components and question types.
- Extended Question and related types to accommodate new configurations and answers.

frontend/src/i18n/en.json

@@ -30,7 +30,7 @@
     "downloadInstructions": "Download Instructions — How to create your own exam JSON",
     "downloadInstructionsIcon": "↓",
     "supportedTypes": "Supported types",
-    "supportedTypesList": "multiple-choice · multiple-select · short-answer · translation · math-input (LaTeX) · essay · match · order",
+    "supportedTypesList": "multiple-choice · multiple-select · short-answer · translation · math-input (LaTeX) · essay · match · order · fill-in-the-blanks · true-false · code-submission · dropdown-completion · numeric-range",
     "trySample": "Try a sample",
     "resumeTitle": "Resume in-progress exam",
     "resumeProgress": "{{answered}}/{{total}} answered",
@@ -381,6 +381,23 @@
     "essay": "Essay",
     "match": "Match",
     "order": "Order",
+    "fillInTheBlanks": "Fill in the Blanks",
+    "trueFalse": "True / False",
+    "codeSubmission": "Code Submission",
+    "dropdownCompletion": "Dropdown Completion",
+    "numericRange": "Numeric Range",
+    "dictation": "Dictation",
+    "grammarCorrection": "Grammar Correction",
+    "flashcard": "Flashcard",
+    "textToCorrect": "Text to Correct",
+    "textToCorrectPlaceholder": "Enter the grammatically incorrect sentence…",
+    "playbackSpeed": "Speed",
+    "revealAnswer": "Reveal Answer",
+    "didntKnow": "Didn't know",
+    "hard": "Hard",
+    "good": "Good",
+    "flashcardFront": "Prompt (front of card)",
+    "flashcardFrontPlaceholder": "Enter the prompt…",
     "correctAnswer": "Correct Answer",
     "correctAnswerPlaceholder": "Enter the correct answer",
     "acceptedForms": "Accepted Forms (optional alternatives)",