Add lessons Phase 6: lesson plans with curriculum tracking

Structured lesson plans with nested sections and items per enrollment.
Deep create in one request, one-active-per-enrollment constraint,
auto-set startedDate/masteredDate on status transitions, progress %
calculation (skipped items excluded). 8 new tests (84 total).

packages/shared/src/schemas/lessons.schema.ts

@@ -131,3 +131,52 @@ export const GradingScaleUpdateSchema = z.object({
   isDefault: z.boolean().optional(),
 })
 export type GradingScaleUpdateInput = z.infer<typeof GradingScaleUpdateSchema>
+
+// --- Lesson Plan schemas ---
+
+export const LessonPlanItemStatus = z.enum(['not_started', 'in_progress', 'mastered', 'skipped'])
+export type LessonPlanItemStatus = z.infer<typeof LessonPlanItemStatus>
+
+const LessonPlanItemInput = z.object({
+  title: z.string().min(1).max(255),
+  description: opt(z.string()),
+  gradingScaleId: opt(z.string().uuid()),
+  targetGradeValue: opt(z.string().max(50)),
+  sortOrder: z.coerce.number().int(),
+})
+
+const LessonPlanSectionInput = z.object({
+  title: z.string().min(1).max(255),
+  description: opt(z.string()),
+  sortOrder: z.coerce.number().int(),
+  items: z.array(LessonPlanItemInput).default([]),
+})
+
+export const LessonPlanCreateSchema = z.object({
+  memberId: z.string().uuid(),
+  enrollmentId: z.string().uuid(),
+  title: z.string().min(1).max(255),
+  description: opt(z.string()),
+  startedDate: opt(z.string()),
+  sections: z.array(LessonPlanSectionInput).default([]),
+})
+export type LessonPlanCreateInput = z.infer<typeof LessonPlanCreateSchema>
+
+export const LessonPlanUpdateSchema = z.object({
+  title: z.string().min(1).max(255).optional(),
+  description: opt(z.string()),
+  isActive: z.boolean().optional(),
+})
+export type LessonPlanUpdateInput = z.infer<typeof LessonPlanUpdateSchema>
+
+export const LessonPlanItemUpdateSchema = z.object({
+  title: z.string().min(1).max(255).optional(),
+  description: opt(z.string()),
+  status: LessonPlanItemStatus.optional(),
+  gradingScaleId: opt(z.string().uuid()),
+  currentGradeValue: opt(z.string().max(50)),
+  targetGradeValue: opt(z.string().max(50)),
+  notes: opt(z.string()),
+  sortOrder: z.coerce.number().int().optional(),
+})
+export type LessonPlanItemUpdateInput = z.infer<typeof LessonPlanItemUpdateSchema>