refactor: RBAC权限系统重构 + UI组件拆分 + 测试修复 + 架构文档

- RBAC: 新增30个权限点、DataScope行级权限、requirePermission守卫，所有57+ Server Action接入权限校验
- UI拆分: exam-form(1623行→11文件)、textbook-reader(744行→7文件)，均降至300行以内
- 测试: 新增5个单元测试文件(19用例)，修复4个集成测试文件(38用例全部通过)
- 架构文档: 新增架构影响地图(004/005)、标准功能清单(006)、差距审计报告(007)
- 项目规则: 架构图优先规则，改码必同步图
- 安全: rehype-sanitize净化、AES加密API Key、权限路由守卫
- 无障碍: skip-link、aria-label、prefers-reduced-motion
- 性能: next/font优化、next/image、代码分割

src/modules/textbooks/components/knowledge-graph.tsx

@@ -0,0 +1,181 @@
+"use client"
+
+import { useMemo } from "react"
+
+import type { KnowledgePoint } from "../types"
+import { cn } from "@/shared/lib/utils"
+import { ScrollArea } from "@/shared/components/ui/scroll-area"
+
+interface GraphNode extends KnowledgePoint {
+  x: number
+  y: number
+}
+
+interface GraphEdge {
+  id: string
+  x1: number
+  y1: number
+  x2: number
+  y2: number
+}
+
+interface GraphLayout {
+  nodes: GraphNode[]
+  edges: GraphEdge[]
+  width: number
+  height: number
+}
+
+function computeGraphLayout(knowledgePoints: KnowledgePoint[]): GraphLayout {
+  if (knowledgePoints.length === 0) {
+    return { nodes: [], edges: [], width: 0, height: 0 }
+  }
+
+  const byId = new Map<string, KnowledgePoint>()
+  for (const kp of knowledgePoints) byId.set(kp.id, kp)
+
+  const children = new Map<string, string[]>()
+  const roots: string[] = []
+
+  for (const kp of knowledgePoints) {
+    if (kp.parentId && byId.has(kp.parentId)) {
+      const arr = children.get(kp.parentId) ?? []
+      arr.push(kp.id)
+      children.set(kp.parentId, arr)
+    } else {
+      roots.push(kp.id)
+    }
+  }
+
+  const levelMap = new Map<string, number>()
+  const levels: string[][] = []
+  const queue = [...roots].map((id) => ({ id, level: 0 }))
+
+  if (queue.length === 0) {
+    for (const kp of knowledgePoints) queue.push({ id: kp.id, level: 0 })
+  }
+
+  while (queue.length > 0) {
+    const item = queue.shift()
+    if (!item) continue
+    if (levelMap.has(item.id)) continue
+    levelMap.set(item.id, item.level)
+    if (!levels[item.level]) levels[item.level] = []
+    levels[item.level].push(item.id)
+    const kids = children.get(item.id) ?? []
+    for (const kid of kids) {
+      if (!levelMap.has(kid)) queue.push({ id: kid, level: item.level + 1 })
+    }
+  }
+
+  for (const kp of knowledgePoints) {
+    if (!levelMap.has(kp.id)) {
+      const level = levels.length
+      levelMap.set(kp.id, level)
+      if (!levels[level]) levels[level] = []
+      levels[level].push(kp.id)
+    }
+  }
+
+  const nodeWidth = 160
+  const nodeHeight = 52
+  const gapX = 40
+  const gapY = 90
+  const maxCount = Math.max(...levels.map((l) => l.length), 1)
+  const width = maxCount * (nodeWidth + gapX) + gapX
+  const height = levels.length * (nodeHeight + gapY) + gapY
+
+  const positions = new Map<string, { x: number; y: number }>()
+  levels.forEach((ids, level) => {
+    ids.forEach((id, index) => {
+      const x = gapX + index * (nodeWidth + gapX)
+      const y = gapY + level * (nodeHeight + gapY)
+      positions.set(id, { x, y })
+    })
+  })
+
+  const nodes = knowledgePoints.map((kp) => {
+    const pos = positions.get(kp.id) ?? { x: gapX, y: gapY }
+    return { ...kp, x: pos.x, y: pos.y }
+  })
+
+  const edges = knowledgePoints
+    .filter((kp) => kp.parentId && positions.has(kp.parentId))
+    .map((kp) => {
+      const parentPos = positions.get(kp.parentId as string)!
+      const childPos = positions.get(kp.id)!
+      return {
+        id: `${kp.parentId}-${kp.id}`,
+        x1: parentPos.x + nodeWidth / 2,
+        y1: parentPos.y + nodeHeight,
+        x2: childPos.x + nodeWidth / 2,
+        y2: childPos.y,
+      }
+    })
+
+  return { nodes, edges, width, height }
+}
+
+interface KnowledgeGraphProps {
+  knowledgePoints: KnowledgePoint[]
+  selectedId: string | null
+  onHighlight: (id: string) => void
+}
+
+export function KnowledgeGraph({ knowledgePoints, selectedId, onHighlight }: KnowledgeGraphProps) {
+  const graphLayout = useMemo(() => computeGraphLayout(knowledgePoints), [knowledgePoints])
+
+  if (knowledgePoints.length === 0) {
+    return (
+      <div className="flex h-full items-center justify-center text-muted-foreground p-4 text-center text-sm">
+        该章节暂无知识点。
+      </div>
+    )
+  }
+
+  return (
+    <ScrollArea className="flex-1 h-full px-2">
+      <div
+        className="relative"
+        style={{ width: graphLayout.width, height: graphLayout.height }}
+      >
+        <svg
+          width={graphLayout.width}
+          height={graphLayout.height}
+          className="absolute inset-0"
+        >
+          {graphLayout.edges.map((edge) => (
+            <line
+              key={edge.id}
+              x1={edge.x1}
+              y1={edge.y1}
+              x2={edge.x2}
+              y2={edge.y2}
+              stroke="hsl(var(--border))"
+              strokeWidth={2}
+            />
+          ))}
+        </svg>
+        {graphLayout.nodes.map((node) => (
+          <button
+            key={node.id}
+            type="button"
+            className={cn(
+              "absolute rounded-lg border bg-card px-3 py-2 text-left text-sm shadow-sm hover:bg-accent/50",
+              selectedId === node.id && "border-primary bg-primary/5"
+            )}
+            style={{ left: node.x, top: node.y, width: 160, height: 52 }}
+            onClick={() => onHighlight(node.id)}
+          >
+            <div className="font-medium truncate">{node.name}</div>
+            {node.description && (
+              <div className="text-[10px] text-muted-foreground truncate">
+                {node.description}
+              </div>
+            )}
+          </button>
+        ))}
+      </div>
+    </ScrollArea>
+  )
+}