feat(exams,homework): add error collection data-access for error book integration

- Add data-access-error-collection in exams module for collecting wrong exam answers

- Add data-access-error-collection in homework module for collecting wrong homework answers

- Update exams actions, exam-ai-generator, data-access, and types

- Update homework actions and data-access-write

src/modules/exams/data-access-error-collection.ts

@@ -0,0 +1,94 @@
+import "server-only"
+
+import { and, eq } from "drizzle-orm"
+
+import { db } from "@/shared/db"
+import { examQuestions, examSubmissions, exams, submissionAnswers } from "@/shared/db/schema"
+
+/**
+ * 错题采集所需的答案数据（单题）
+ */
+export type AnswerForErrorCollection = {
+  questionId: string
+  answerContent: unknown
+  score: number | null
+  feedback: string | null
+  maxScore: number
+}
+
+/**
+ * 考试提交的错题采集数据
+ */
+export type ExamSubmissionDataForErrorCollection = {
+  examId: string
+  subjectId: string | null
+  answers: AnswerForErrorCollection[]
+}
+
+/**
+ * 跨模块接口：获取考试提交的错题采集数据。
+ *
+ * 供 error-book 模块调用，避免 error-book 直接查询 examSubmissions、
+ * submissionAnswers、examQuestions、exams 等属于 exams 模块的表。
+ *
+ * 返回该提交的所有答案（含得分、反馈、满分），由 error-book 模块
+ * 自行筛选错题（score < maxScore）并采集。
+ *
+ * @param submissionId 考试提交 ID
+ * @param studentId 学生 ID（用于校验提交归属）
+ * @returns 提交数据；若提交不存在或 studentId 不匹配则返回 null
+ */
+export async function getExamSubmissionDataForErrorCollection(
+  submissionId: string,
+  studentId: string,
+): Promise<ExamSubmissionDataForErrorCollection | null> {
+  const submission = await db.query.examSubmissions.findFirst({
+    where: and(
+      eq(examSubmissions.id, submissionId),
+      eq(examSubmissions.studentId, studentId),
+    ),
+    columns: { id: true, examId: true },
+  })
+
+  if (!submission) return null
+
+  // 并行获取考试学科、提交答案、题目满分
+  const [exam, answers, examQuestionScores] = await Promise.all([
+    db.query.exams.findFirst({
+      where: eq(exams.id, submission.examId),
+      columns: { subjectId: true },
+    }),
+    db
+      .select({
+        questionId: submissionAnswers.questionId,
+        answerContent: submissionAnswers.answerContent,
+        score: submissionAnswers.score,
+        feedback: submissionAnswers.feedback,
+      })
+      .from(submissionAnswers)
+      .where(eq(submissionAnswers.submissionId, submissionId)),
+    db
+      .select({
+        questionId: examQuestions.questionId,
+        maxScore: examQuestions.score,
+      })
+      .from(examQuestions)
+      .where(eq(examQuestions.examId, submission.examId)),
+  ])
+
+  const maxScoreMap = new Map(examQuestionScores.map((q) => [q.questionId, q.maxScore ?? 0]))
+
+  const mappedAnswers: AnswerForErrorCollection[] = answers.map((a) => ({
+    questionId: a.questionId,
+    answerContent: a.answerContent,
+    score: a.score,
+    feedback: a.feedback,
+    maxScore: maxScoreMap.get(a.questionId) ?? 0,
+  }))
+
+  return {
+    examId: submission.examId,
+    subjectId: exam?.subjectId ?? null,
+    answers: mappedAnswers,
+  }
+}