feat: 调整 ExamSelectModal 样式，移除内容内边距；修正 ExamPractice 提交函数调用

Author: ayozoo

client/src/components/ExamSelectModal.tsx

@@ -33,7 +33,6 @@ export function ExamSelectModal({
       width={600}
       styles={{
         body: { padding: 0, maxHeight: '60vh', overflowY: 'auto' },
-        content: { padding: 0 },
       }}
       className="exam-select-modal"
     >

client/src/pages/ExamPractice.tsx

@@ -28,7 +28,7 @@ export function ExamPractice({ examList, currentExam, loading, onSelectExam }: E
   useKeyboardShortcuts({
     onPrev: () => currentIndex > 0 && handlePrev(),
     onNext: () => currentExam && currentIndex < currentExam.questions.length - 1 && handleNext(),
-    onSubmit: () => !submittedMap[currentIndex] && handleSubmit(),
+    onSubmit: () => !submittedMap[currentIndex] && handleSubmitCurrent(),
     onSelectOption: (index) => {
       const q = currentExam?.questions[currentIndex];
       if (q && q.options && q.options[index] && !submittedMap[currentIndex]) {