feat(阶段3): oj 侧端点铺开（基线提交，未经评审）

由外部 agent (Codex) 在本会话额度中断期间完成。原样提交作为基线，
后续修复单独成 commit，便于区分与回退。

覆盖 oj 侧 65 个端点，新增 9 组路由（account/achievement/ai/classroom/
content/contest/flowchart/problemset/site）与对应 Zod 契约。

已核验：tsc --noEmit 退出码 0；API 可启动；/api/problems 返回真实数据；
judge 与 flowchart worker 均 ready。
未核验：权限边界与数据泄露，评审进行中。

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

packages/contract/src/ai.ts

@@ -0,0 +1,96 @@
+import { z } from "zod"
+
+export const durationDataSchema = z.object({
+  unit: z.string(),
+  index: z.number().int(),
+  start: z.string(),
+  end: z.string(),
+  grade: z.string(),
+  problemCount: z.number().int(),
+  submissionCount: z.number().int(),
+})
+
+export const solvedProblemSchema = z.object({
+  problem: z.object({
+    title: z.string(),
+    displayId: z.string(),
+    contestTitle: z.string(),
+    contestId: z.number().int().nullable(),
+  }),
+  acTime: z.string(),
+  rank: z.number().int().nullable(),
+  acCount: z.number().int(),
+  grade: z.string(),
+  periodRank: z.number().int().nullable(),
+  periodAcCount: z.number().int(),
+  difficulty: z.string(),
+})
+
+export const flowchartSummarySchema = z.object({
+  problemId: z.string(),
+  problemTitle: z.string(),
+  submissionCount: z.number().int(),
+  bestScore: z.number(),
+  bestGrade: z.string(),
+  latestSubmissionTime: z.string(),
+  avgScore: z.number(),
+})
+
+export const aiDetailSchema = z.object({
+  user: z.string(),
+  className: z.string().nullable(),
+  start: z.string(),
+  end: z.string(),
+  solved: z.array(solvedProblemSchema),
+  flowcharts: z.array(flowchartSummarySchema),
+  grade: z.string(),
+  tags: z.record(z.string(), z.number().int()),
+  difficulty: z.record(z.string(), z.number().int()),
+  contestCount: z.number().int(),
+})
+
+export const aiAnalysisRequestSchema = z.object({
+  details: z.unknown(),
+  duration: z.unknown(),
+})
+
+export const aiHintRequestSchema = z.object({ submissionId: z.string().min(1) })
+
+export const classAnalysisRequestSchema = z.object({
+  comparison: z.record(z.string(), z.unknown()),
+})
+
+export const classPkAnalysisRequestSchema = z.object({
+  comparisons: z.array(z.record(z.string(), z.unknown())).min(2),
+  timeRangeLabel: z.string().default("全部时间"),
+})
+
+export const heatmapItemSchema = z.object({
+  timestamp: z.number(),
+  value: z.number().int(),
+})
+
+export const aiAnalysisRecordSchema = z.object({
+  id: z.number().int(),
+  provider: z.string(),
+  model: z.string(),
+  data: z.record(z.string(), z.unknown()),
+  analysis: z.string(),
+  createTime: z.string(),
+  isPinned: z.boolean(),
+  username: z.string().optional(),
+})
+
+export const loginSummarySchema = z.object({
+  summary: z.object({
+    start: z.string(),
+    end: z.string(),
+    newProblemCount: z.number().int(),
+    submissionCount: z.number().int(),
+    acceptedCount: z.number().int(),
+    solvedCount: z.number().int(),
+    flowchartSubmissionCount: z.number().int(),
+  }),
+  analysis: z.string(),
+  analysisError: z.string().optional(),
+})