Add Phase 7: grade history and session-plan item linking

- New tables: lesson_plan_item_grade_history (append-only), lesson_session_plan_item
- Grading an item updates current_grade_value and creates immutable history record
- Grading a not_started item auto-transitions it to in_progress
- Linking items to a session also auto-transitions not_started items
- Link operation is idempotent — re-linking same items produces no duplicates
- Endpoints: POST/GET /lesson-plan-items/:id/grades, GET /lesson-plan-items/:id/grade-history
- Endpoints: POST/GET /lesson-sessions/:id/plan-items
- 8 new integration tests

packages/backend/src/routes/v1/lessons.ts

@@ -18,10 +18,12 @@ import {
   LessonPlanCreateSchema,
   LessonPlanUpdateSchema,
   LessonPlanItemUpdateSchema,
+  GradeCreateSchema,
+  SessionPlanItemsSchema,
   InstructorBlockedDateCreateSchema,
   StoreClosureCreateSchema,
 } from '@lunarfront/shared/schemas'
-import { InstructorService, LessonTypeService, ScheduleSlotService, EnrollmentService, LessonSessionService, GradingScaleService, LessonPlanService, LessonPlanItemService, InstructorBlockedDateService, StoreClosureService } from '../../services/lesson.service.js'
+import { InstructorService, LessonTypeService, ScheduleSlotService, EnrollmentService, LessonSessionService, GradingScaleService, LessonPlanService, LessonPlanItemService, GradeHistoryService, SessionPlanItemService, InstructorBlockedDateService, StoreClosureService } from '../../services/lesson.service.js'
 
 export const lessonRoutes: FastifyPluginAsync = async (app) => {
   // --- Instructors ---
@@ -383,6 +385,44 @@ export const lessonRoutes: FastifyPluginAsync = async (app) => {
     return reply.send(item)
   })
 
+  // --- Grade History ---
+
+  app.post('/lesson-plan-items/:id/grades', { preHandler: [app.authenticate, app.requirePermission('lessons.edit')] }, async (request, reply) => {
+    const { id } = request.params as { id: string }
+    const parsed = GradeCreateSchema.safeParse(request.body)
+    if (!parsed.success) {
+      return reply.status(400).send({ error: { message: 'Validation failed', details: parsed.error.flatten(), statusCode: 400 } })
+    }
+    const result = await GradeHistoryService.create(app.db, id, parsed.data, request.user.id)
+    if (!result) return reply.status(404).send({ error: { message: 'Lesson plan item not found', statusCode: 404 } })
+    return reply.status(201).send(result)
+  })
+
+  app.get('/lesson-plan-items/:id/grade-history', { preHandler: [app.authenticate, app.requirePermission('lessons.view')] }, async (request, reply) => {
+    const { id } = request.params as { id: string }
+    const history = await GradeHistoryService.list(app.db, id)
+    return reply.send(history)
+  })
+
+  // --- Session Plan Items ---
+
+  app.post('/lesson-sessions/:id/plan-items', { preHandler: [app.authenticate, app.requirePermission('lessons.edit')] }, async (request, reply) => {
+    const { id } = request.params as { id: string }
+    const parsed = SessionPlanItemsSchema.safeParse(request.body)
+    if (!parsed.success) {
+      return reply.status(400).send({ error: { message: 'Validation failed', details: parsed.error.flatten(), statusCode: 400 } })
+    }
+    const result = await SessionPlanItemService.linkItems(app.db, id, parsed.data)
+    if (result === null) return reply.status(404).send({ error: { message: 'Lesson session not found', statusCode: 404 } })
+    return reply.status(201).send({ linked: result.length, items: result })
+  })
+
+  app.get('/lesson-sessions/:id/plan-items', { preHandler: [app.authenticate, app.requirePermission('lessons.view')] }, async (request, reply) => {
+    const { id } = request.params as { id: string }
+    const items = await SessionPlanItemService.listForSession(app.db, id)
+    return reply.send(items)
+  })
+
   // --- Instructor Blocked Dates ---
 
   app.post('/instructors/:id/blocked-dates', { preHandler: [app.authenticate, app.requirePermission('lessons.admin')] }, async (request, reply) => {