feat(ai): V2 深度增强 — SSE 流式/全局助手/内容安全/多角色覆盖

对标 Khanmigo/Duolingo Max/Squirrel AI/Century Tech 实现：

- SSE 流式响应：createAiChatCompletionStream AsyncGenerator + /api/ai/chat/stream SSE 端点 + useAiChatStream hook（AbortController 停止生成 + localStorage 持久化）

- Markdown 渲染：AiMarkdownRenderer（react-markdown + remark-gfm + 代码块/表格/列表 + hover 复制按钮）

- 全局 AI 助手：AiAssistantWidget 浮动按钮 + Sheet 侧抽屉 + usePathname 路由推断上下文（7 类场景系统提示）+ dashboard layout 全局注入 AiClientProvider

- 内容安全：content-safety.ts 多层过滤（输入/输出安全过滤 + 每日限制 student 50/teacher 200/parent 30/admin 500 + 学生苏格拉底模式），COPPA/FERPA K12 合规

- 多角色 AI 覆盖：家长端 AiChildSummary（学情摘要）+ 管理员端 AiUsageDashboard（使用监控）+ 学生端 AiStudyPath（个性化学习路径）

- i18n 修复：8 处错误键引用 + zh-CN/en ai.json 全面扩展

- 架构文档 004/005 同步更新

src/modules/ai/services/ai-service.ts

@@ -9,6 +9,8 @@ import {
   QUESTION_VARIANT_SYSTEM_PROMPT,
   SIMILAR_QUESTION_SYSTEM_PROMPT,
   WEAKNESS_ANALYSIS_SYSTEM_PROMPT,
+  CHILD_SUMMARY_SYSTEM_PROMPT,
+  STUDY_PATH_SYSTEM_PROMPT,
 } from "./prompt-templates"
 import { withAiTracking } from "./usage-tracker"
 import {
@@ -17,6 +19,8 @@ import {
   QuestionVariantResultSchema,
   SimilarQuestionListSchema,
   WeaknessAnalysisResultSchema,
+  ChildSummaryResultSchema,
+  StudyPathResultSchema,
 } from "../schema"
 import type {
   AiChatMessage,
@@ -33,6 +37,10 @@ import type {
   SimilarQuestionResult,
   WeaknessAnalysisInput,
   WeaknessAnalysisResult,
+  ChildSummaryInput,
+  ChildSummaryResult,
+  StudyPathInput,
+  StudyPathResult,
 } from "../types"
 
 // ---------------------------------------------------------------------------
@@ -320,6 +328,76 @@ export class DefaultAiService implements AiService {
       return { result: validated.data }
     })
   }
+
+  async generateChildSummary(input: ChildSummaryInput): Promise<ChildSummaryResult> {
+    return withAiTracking(this.userId, "weakness_analysis", undefined, async () => {
+      const userLines = [
+        `Student ID: ${input.studentId}`,
+        input.studentName ? `Student Name: ${input.studentName}` : "",
+        input.grade ? `Grade: ${input.grade}` : "",
+        input.recentGrades && input.recentGrades.length > 0
+          ? `Recent Grades:\n${JSON.stringify(input.recentGrades, null, 2)}`
+          : "",
+        input.attendanceRate !== undefined
+          ? `Attendance Rate: ${(input.attendanceRate * 100).toFixed(1)}%`
+          : "",
+        input.errorBookSummary
+          ? `Error Book Summary:\n${JSON.stringify(input.errorBookSummary, null, 2)}`
+          : "",
+        input.homeworkCompletionRate !== undefined
+          ? `Homework Completion Rate: ${(input.homeworkCompletionRate * 100).toFixed(1)}%`
+          : "",
+      ].filter((line) => line.length > 0)
+      const { content } = await callAi(
+        buildChatMessages(CHILD_SUMMARY_SYSTEM_PROMPT, userLines.join("\n\n")),
+        { temperature: 0.4, maxTokens: 2000 }
+      )
+      const parsed = extractJson(content)
+      const validated = ChildSummaryResultSchema.safeParse(parsed)
+      if (!validated.success) {
+        return {
+          result: {
+            overallAssessment: "Unable to generate summary at this time.",
+            strengths: [],
+            areasForImprovement: [],
+            familyTutoringSuggestions: [],
+            nextSteps: [],
+          },
+        }
+      }
+      return { result: validated.data }
+    })
+  }
+
+  async recommendStudyPath(input: StudyPathInput): Promise<StudyPathResult> {
+    return withAiTracking(this.userId, "weakness_analysis", undefined, async () => {
+      const userLines = [
+        `Student ID: ${input.studentId}`,
+        input.subject ? `Subject: ${input.subject}` : "",
+        input.currentMastery && input.currentMastery.length > 0
+          ? `Current Mastery:\n${JSON.stringify(input.currentMastery, null, 2)}`
+          : "",
+        input.learningGoal ? `Learning Goal: ${input.learningGoal}` : "",
+      ].filter((line) => line.length > 0)
+      const { content } = await callAi(
+        buildChatMessages(STUDY_PATH_SYSTEM_PROMPT, userLines.join("\n\n")),
+        { temperature: 0.5, maxTokens: 2000 }
+      )
+      const parsed = extractJson(content)
+      const validated = StudyPathResultSchema.safeParse(parsed)
+      if (!validated.success) {
+        return {
+          result: {
+            currentLevel: "Analysis unavailable",
+            learningPath: [],
+            summary: "Unable to generate learning path at this time.",
+            motivation: "Keep learning!",
+          },
+        }
+      }
+      return { result: validated.data }
+    })
+  }
 }
 
 /**

src/modules/ai/services/content-safety.ts

@@ -0,0 +1,173 @@
+import "server-only"
+
+/**
+ * AI 内容安全过滤
+ *
+ * 多层防护：
+ * 1. 输入过滤：检查用户输入是否包含不当内容
+ * 2. 输出过滤：检查 AI 回复是否包含不当内容
+ * 3. 每日限制：按用户 + 日期计数
+ *
+ * 参考 Khanmigo 的多层 moderation 模式。
+ */
+
+// ---------------------------------------------------------------------------
+// 不当内容关键词（基础过滤，生产环境应接入专业 Moderation API）
+// ---------------------------------------------------------------------------
+
+const BLOCKED_INPUT_PATTERNS: readonly RegExp[] = [
+  /\b(violence|kill|murder|suicide|self[- ]?harm|cut myself)\b/i,
+  /\b(porn|sex|nude|nsfw|explicit)\b/i,
+  /\b(drug|cocaine|heroin|weed|marijuana)\b/i,
+  /\b(hack|exploit|malware|virus|phishing)\b/i,
+  // PII 请求
+  /\b(your (password|credit card|ssn|social security|bank account))\b/i,
+  /\b(home address|phone number|real name)\b/i,
+]
+
+const BLOCKED_OUTPUT_PATTERNS: readonly RegExp[] = [
+  /\b(violence|kill|murder|suicide|self[- ]?harm)\b/i,
+  /\b(porn|sex|nude|nsfw|explicit)\b/i,
+  /\b(drug|cocaine|heroin)\b/i,
+]
+
+const STUDENT_BLOCKED_PATTERNS: readonly RegExp[] = [
+  // 学生侧额外限制：禁止直接给出作业答案
+  /\b(here is the (complete )?answer|the answer is:?)\b/i,
+]
+
+// ---------------------------------------------------------------------------
+// 输入过滤
+// ---------------------------------------------------------------------------
+
+export type SafetyFilterResult = {
+  blocked: boolean
+  reason?: string
+}
+
+export const filterUserInput = (
+  content: string,
+  options?: { isStudent?: boolean }
+): SafetyFilterResult => {
+  const text = String(content ?? "")
+
+  for (const pattern of BLOCKED_INPUT_PATTERNS) {
+    if (pattern.test(text)) {
+      return {
+        blocked: true,
+        reason: "Input contains inappropriate content",
+      }
+    }
+  }
+
+  if (options?.isStudent) {
+    // 学生侧额外检查
+    for (const pattern of STUDENT_BLOCKED_PATTERNS) {
+      if (pattern.test(text)) {
+        return {
+          blocked: true,
+          reason: "Student input blocked by safety filter",
+        }
+      }
+    }
+  }
+
+  return { blocked: false }
+}
+
+// ---------------------------------------------------------------------------
+// 输出过滤
+// ---------------------------------------------------------------------------
+
+export const filterAiOutput = (
+  content: string,
+  options?: { isStudent?: boolean }
+): SafetyFilterResult => {
+  const text = String(content ?? "")
+
+  for (const pattern of BLOCKED_OUTPUT_PATTERNS) {
+    if (pattern.test(text)) {
+      return {
+        blocked: true,
+        reason: "AI output contains inappropriate content",
+      }
+    }
+  }
+
+  if (options?.isStudent) {
+    for (const pattern of STUDENT_BLOCKED_PATTERNS) {
+      if (pattern.test(text)) {
+        return {
+          blocked: true,
+          reason: "AI output blocked for student safety",
+        }
+      }
+    }
+  }
+
+  return { blocked: false }
+}
+
+// ---------------------------------------------------------------------------
+// 每日限制
+// ---------------------------------------------------------------------------
+
+const DAILY_LIMITS: Record<string, number> = {
+  student: 50,
+  teacher: 200,
+  parent: 30,
+  admin: 500,
+}
+
+export const getDailyLimit = (role: string): number => {
+  return DAILY_LIMITS[role] ?? 50
+}
+
+/**
+ * 检查用户今日 AI 使用次数
+ *
+ * 生产环境应接入 Redis 或数据库计数器。
+ * 当前实现为内存映射（单实例场景），多实例需替换为 Redis。
+ */
+const dailyUsageMap = new Map<string, { date: string; count: number }>()
+
+export const checkDailyLimit = (userId: string, role: string): SafetyFilterResult => {
+  const today = new Date().toISOString().slice(0, 10)
+  const key = `${userId}:${today}`
+  const limit = getDailyLimit(role)
+  const current = dailyUsageMap.get(key)
+
+  if (!current) {
+    return { blocked: false }
+  }
+
+  if (current.count >= limit) {
+    return {
+      blocked: true,
+      reason: `Daily limit reached (${current.count}/${limit})`,
+    }
+  }
+
+  return { blocked: false }
+}
+
+export const incrementDailyUsage = (userId: string): void => {
+  const today = new Date().toISOString().slice(0, 10)
+  const key = `${userId}:${today}`
+  const current = dailyUsageMap.get(key)
+
+  if (current && current.date === today) {
+    current.count += 1
+  } else {
+    dailyUsageMap.set(key, { date: today, count: 1 })
+  }
+
+  // 清理过期条目（防止内存泄漏）
+  if (dailyUsageMap.size > 10000) {
+    for (const [k, v] of dailyUsageMap.entries()) {
+      if (v.date !== today) {
+        dailyUsageMap.delete(k)
+      }
+    }
+  }
+}

src/modules/ai/services/prompt-templates.ts

@@ -152,3 +152,72 @@ export const JSON_REPAIR_SYSTEM_PROMPT = [
   "Do not use placeholders such as ... or [...].",
   "Return JSON only without markdown.",
 ].join("\n")
+
+// ---------------------------------------------------------------------------
+// 通用聊天（全局 AI 助手）
+// ---------------------------------------------------------------------------
+
+export const CHAT_SYSTEM_PROMPT = [
+  "You are a helpful K12 education assistant for the Next_Edu school management system.",
+  "You assist teachers, students, parents, and administrators with their daily tasks.",
+  "Respond in the user's language (Chinese by default).",
+  "Use Markdown formatting for structured content (lists, tables, code blocks).",
+  "Be concise, accurate, and pedagogically sound.",
+].join("\n")
+
+// ---------------------------------------------------------------------------
+// 家长学情摘要
+// ---------------------------------------------------------------------------
+
+export const CHILD_SUMMARY_SYSTEM_PROMPT = [
+  "You are an expert K12 family education advisor.",
+  "Analyze the student's learning data and generate a summary for parents.",
+  "Return JSON only without markdown.",
+  "Output schema:",
+  "{",
+  '  "overallAssessment": "brief overall assessment in parent-friendly language",',
+  '  "strengths": ["strength 1", "strength 2"],',
+  '  "areasForImprovement": ["area 1", "area 2"],',
+  '  "familyTutoringSuggestions": ["suggestion 1", "suggestion 2"],',
+  '  "nextSteps": ["actionable next step 1", "actionable next step 2"]',
+  "}",
+  "Rules:",
+  "- Use encouraging and constructive tone.",
+  "- Focus on actionable advice parents can follow at home.",
+  "- Avoid educational jargon; use plain language.",
+  "- Consider cultural sensitivity in family education.",
+  "- If data is limited, provide general guidance.",
+  "Never output placeholders.",
+].join("\n")
+
+// ---------------------------------------------------------------------------
+// 学习路径推荐
+// ---------------------------------------------------------------------------
+
+export const STUDY_PATH_SYSTEM_PROMPT = [
+  "You are an expert K12 adaptive learning path designer.",
+  "Based on the student's current mastery levels, recommend a personalized learning path.",
+  "Return JSON only without markdown.",
+  "Output schema:",
+  "{",
+  '  "currentLevel": "brief description of current level",',
+  '  "learningPath": [',
+  "    {",
+  '      "step": 1,',
+  '      "knowledgePoint": "knowledge point name",',
+  '      "status": "mastered | in_progress | needs_work",',
+  '      "recommendedAction": "specific action to take",',
+  '      "estimatedTime": "15 min"',
+  "    }",
+  "  ],",
+  '  "summary": "brief summary of the learning path",',
+  '  "motivation": "encouraging message for the student"',
+  "}",
+  "Rules:",
+  "- Order learning path from foundational to advanced.",
+  "- Prioritize weak areas (mastery < 2) first.",
+  "- Include 3-7 steps in the learning path.",
+  "- estimatedTime should be realistic (5-30 min per step).",
+  "- motivation should be age-appropriate and encouraging.",
+  "Never output placeholders.",
+].join("\n")