refactor(lesson-preparation): V2 审计深度修复 — Server Actions i18n + 错误码模式 + 类型断言清零 + a11y 深度修复 + Tracker 埋点接入

V2-1: 12 个 Server Action 通过 getTranslations 翻译错误消息；Service/DataAccess 层抛出错误码异常（PublishServiceError/LessonPlanDataError），Actions 层通过 PUBLISH_ERROR_KEY_MAP 翻译为 i18n 消息
V2-2: SYSTEM_TEMPLATES name/title 改为 i18n 键，createLessonPlan 接受 translateTitle 函数在服务端翻译后存储到 DB
V2-3: 8 处 as unknown as 断言替换为显式类型映射函数（mapRowToLessonPlan/mapRowToListItem/mapRowToTemplate/mapRowToVersion）+ 类型守卫（isLessonPlanStatus/isTemplateType/isTemplateScope）
V2-4: MiniMap nodeColor 复用 lib/node-summary.ts 的 getNodeColor
V2-5: a11y 深度修复 — lesson-plan-filters/exercise-block/inline-question-editor 的 select 添加 label htmlFor 关联；exercise-block 题目列表改为 ul/li；node-editor 画布添加 role=application + 键盘导航配置
V2-6: Tracker 埋点接入 — 新增 useLessonPlanTrackerSafe hook，在 create/save/publish/revert/duplicate/archive 6 处调用 tracker.track

同步更新架构图 004 和 005 文档

src/modules/lesson-preparation/components/node-editor.tsx

@@ -19,6 +19,7 @@ import "@xyflow/react/dist/style.css";
 import { useLessonPlanEditor } from "../hooks/use-lesson-plan-editor";
 import { LessonNode } from "./nodes/lesson-node";
 import { toRfNodes, toRfEdges } from "../lib/rf-mappers";
+import { getNodeColor } from "../lib/node-summary";
 import type { LessonPlanNode } from "../types";
 
 const nodeTypes = { lesson: LessonNode };
@@ -87,7 +88,7 @@ export function NodeEditor({}: Props) {
   );
 
   return (
-    <div className="w-full h-full relative">
+    <div className="w-full h-full relative" role="application" aria-label={t("editor.canvasLabel")}>
       {doc.nodes.length === 0 && (
         <div className="absolute inset-0 flex items-center justify-center pointer-events-none z-10">
           <div className="text-center text-on-surface-variant">
@@ -107,6 +108,12 @@ export function NodeEditor({}: Props) {
         onPaneClick={() => selectNode(null)}
         fitView
         fitViewOptions={{ padding: 0.2, maxZoom: 1.2 }}
+        nodesFocusable
+        nodesDraggable
+        edgesFocusable
+        elementsSelectable
+        deleteKeyCode={["Backspace", "Delete"]}
+        multiSelectionKeyCode={["Shift", "Meta", "Control"]}
         defaultEdgeOptions={{
           animated: true,
           style: { stroke: "#1976d2", strokeWidth: 2 },
@@ -126,21 +133,7 @@ export function NodeEditor({}: Props) {
           nodeColor={(n) => {
             const nodeData = (n.data as { node?: LessonPlanNode }).node;
             if (!nodeData) return "#9e9e9e";
-            const colors: Record<string, string> = {
-              objective: "#4caf50",
-              key_point: "#f44336",
-              import: "#2196f3",
-              new_teaching: "#9c27b0",
-              consolidation: "#ff9800",
-              summary: "#607d8b",
-              homework: "#795548",
-              blackboard: "#009688",
-              text_study: "#3f51b5",
-              exercise: "#e91e63",
-              rich_text: "#9e9e9e",
-              reflection: "#cddc39",
-            };
-            return colors[nodeData.type] ?? "#9e9e9e";
+            return getNodeColor(nodeData.type);
           }}
         />
       </ReactFlow>