feat(lesson-preparation): add AI evaluation, analytics, attachments, calendar, comments, review, substitutes, formative, and version diff

- Add actions-ai-evaluation, actions-analytics, actions-attachments, actions-calendar, actions-comments, actions-formative, actions-questions, actions-review, actions-substitutes

- Add corresponding data-access layers for each new action module

- Add calendar-view, curriculum-map-view, version-diff-viewer components

- Add editor-slice, selection-slice, version-slice hooks for state management

- Add document-diff and scope-check lib utilities

- Add default-question-service and external-questions-bridge services

src/modules/lesson-preparation/hooks/selection-slice.ts

@@ -0,0 +1,17 @@
+import type { StateCreator } from "zustand";
+import type { EditorState } from "./use-lesson-plan-editor";
+
+export interface SelectionSlice {
+  selectedNodeId: string | null;
+  selectNode: (id: string | null) => void;
+}
+
+export const createSelectionSlice: StateCreator<
+  EditorState,
+  [],
+  [],
+  SelectionSlice
+> = (set) => ({
+  selectedNodeId: null,
+  selectNode: (id) => set({ selectedNodeId: id }),
+});