feat(lesson-preparation): add readonly view, anchor node selector, and type guards

- Add lesson-plan-readonly-view for viewing published plans

- Add anchor-node-selector and textbook-segments for canvas anchor positioning

- Add i18n-errors and type-guards lib utilities

- Add lesson-plan-provider-setup for provider initialization

- Update actions, data-access (knowledge, versions, main), publish-service

- Update blocks (blackboard, exercise, homework, import, key-point, objective, reflection)

- Update editor, node-editor, node-edit-panel, pickers, and providers

src/modules/lesson-preparation/components/blocks/blackboard-block.tsx

@@ -4,6 +4,7 @@ import { useState } from "react";
 import { useTranslations } from "next-intl";
 import { Tag } from "lucide-react";
 import type { BlackboardBlockData } from "../../types";
+import { isBlackboardLayout } from "../../lib/type-guards";
 import { KnowledgePointPicker } from "../knowledge-point-picker";
 
 interface Props {
@@ -30,12 +31,12 @@ export function BlackboardBlock({ data, textbookId, chapterId, onUpdate }: Props
         </label>
         <select
           value={data.layout}
-          onChange={(e) =>
-            onUpdate({
-              ...data,
-              layout: e.target.value as BlackboardBlockData["layout"],
-            })
-          }
+          onChange={(e) => {
+            const value = e.target.value;
+            if (isBlackboardLayout(value)) {
+              onUpdate({ ...data, layout: value });
+            }
+          }}
           className="w-full text-sm border border-outline-variant rounded px-2 py-1 bg-surface"
         >
           {LAYOUTS.map((l) => (

src/modules/lesson-preparation/components/blocks/exercise-block.tsx

@@ -12,8 +12,8 @@ import { Plus, Trash2 } from "lucide-react";
 import type {
   ExerciseBlockData,
   ExerciseItem,
-  ExercisePurpose,
 } from "../../types";
+import { isExercisePurpose } from "../../lib/type-guards";
 
 interface Props {
   blockId: string;
@@ -59,9 +59,12 @@ export function ExerciseBlock({ blockId, data, classes, textbookId, chapterId }:
         <select
           id={`exercise-purpose-${blockId}`}
           value={data.purpose}
-          onChange={(e) =>
-            update({ purpose: e.target.value as ExercisePurpose })
-          }
+          onChange={(e) => {
+            const value = e.target.value;
+            if (isExercisePurpose(value)) {
+              update({ purpose: value });
+            }
+          }}
           className="border rounded px-2 py-1 text-sm"
         >
           <option value="class_practice">{t("exercise.purpose.class_practice")}</option>

src/modules/lesson-preparation/components/blocks/homework-block.tsx

@@ -3,6 +3,7 @@
 import { useTranslations } from "next-intl";
 import { Plus, Trash2 } from "lucide-react";
 import type { HomeworkAssignment, HomeworkBlockData } from "../../types";
+import { isHomeworkType } from "../../lib/type-guards";
 import { Button } from "@/shared/components/ui/button";
 
 interface Props {
@@ -45,11 +46,12 @@ export function HomeworkBlock({ data, onUpdate }: Props) {
         <div key={idx} className="flex items-start gap-2">
           <select
             value={item.type}
-            onChange={(e) =>
-              updateItem(idx, {
-                type: e.target.value as HomeworkAssignment["type"],
-              })
-            }
+            onChange={(e) => {
+              const value = e.target.value;
+              if (isHomeworkType(value)) {
+                updateItem(idx, { type: value });
+              }
+            }}
             className="text-xs border border-outline-variant rounded px-1 py-1 bg-surface"
           >
             {TYPES.map((tp) => (

src/modules/lesson-preparation/components/blocks/import-block.tsx

@@ -2,6 +2,7 @@
 
 import { useTranslations } from "next-intl";
 import type { ImportBlockData } from "../../types";
+import { isImportMethod } from "../../lib/type-guards";
 
 interface Props {
   data: ImportBlockData;
@@ -24,9 +25,12 @@ export function ImportBlock({ data, onUpdate }: Props) {
         </label>
         <select
           value={data.method}
-          onChange={(e) =>
-            onUpdate({ ...data, method: e.target.value as ImportBlockData["method"] })
-          }
+          onChange={(e) => {
+            const value = e.target.value;
+            if (isImportMethod(value)) {
+              onUpdate({ ...data, method: value });
+            }
+          }}
           className="w-full text-sm border border-outline-variant rounded px-2 py-1 bg-surface"
         >
           {METHODS.map((m) => (

src/modules/lesson-preparation/components/blocks/key-point-block.tsx

@@ -3,6 +3,7 @@
 import { useTranslations } from "next-intl";
 import { Plus, Trash2 } from "lucide-react";
 import type { KeyPointBlockData, KeyPointItem } from "../../types";
+import { isKeyPointType } from "../../lib/type-guards";
 import { Button } from "@/shared/components/ui/button";
 
 interface Props {
@@ -45,9 +46,12 @@ export function KeyPointBlock({ data, onUpdate }: Props) {
         <div key={idx} className="flex items-start gap-2">
           <select
             value={item.type}
-            onChange={(e) =>
-              updateItem(idx, { type: e.target.value as KeyPointItem["type"] })
-            }
+            onChange={(e) => {
+              const value = e.target.value;
+              if (isKeyPointType(value)) {
+                updateItem(idx, { type: value });
+              }
+            }}
             className="text-xs border border-outline-variant rounded px-1 py-1 bg-surface"
           >
             {TYPES.map((tp) => (

src/modules/lesson-preparation/components/blocks/objective-block.tsx

@@ -3,6 +3,7 @@
 import { useTranslations } from "next-intl";
 import { Plus, Trash2 } from "lucide-react";
 import type { ObjectiveBlockData, ObjectiveItem } from "../../types";
+import { isObjectiveDimension } from "../../lib/type-guards";
 import { Button } from "@/shared/components/ui/button";
 
 interface Props {
@@ -48,11 +49,12 @@ export function ObjectiveBlock({ data, onUpdate }: Props) {
         <div key={idx} className="flex items-start gap-2">
           <select
             value={item.dimension}
-            onChange={(e) =>
-              updateItem(idx, {
-                dimension: e.target.value as ObjectiveItem["dimension"],
-              })
-            }
+            onChange={(e) => {
+              const value = e.target.value;
+              if (isObjectiveDimension(value)) {
+                updateItem(idx, { dimension: value });
+              }
+            }}
             className="text-xs border border-outline-variant rounded px-1 py-1 bg-surface"
           >
             {DIMENSIONS.map((d) => (

src/modules/lesson-preparation/components/blocks/reflection-block.tsx

@@ -3,6 +3,7 @@
 import { useTranslations } from "next-intl";
 import { Plus, Trash2 } from "lucide-react";
 import type { ReflectionBlockData, ReflectionItem } from "../../types";
+import { isReflectionAspect } from "../../lib/type-guards";
 import { Button } from "@/shared/components/ui/button";
 
 interface Props {
@@ -45,11 +46,12 @@ export function ReflectionBlock({ data, onUpdate }: Props) {
         <div key={idx} className="flex items-start gap-2">
           <select
             value={item.aspect}
-            onChange={(e) =>
-              updateItem(idx, {
-                aspect: e.target.value as ReflectionItem["aspect"],
-              })
-            }
+            onChange={(e) => {
+              const value = e.target.value;
+              if (isReflectionAspect(value)) {
+                updateItem(idx, { aspect: value });
+              }
+            }}
             className="text-xs border border-outline-variant rounded px-1 py-1 bg-surface"
           >
             {ASPECTS.map((a) => (