Add Phase 8: lesson plan templates with deep-copy instantiation

- New tables: lesson_plan_template, lesson_plan_template_section, lesson_plan_template_item
- skill_level enum: beginner, intermediate, advanced, all_levels
- Templates are reusable curriculum definitions independent of any member/enrollment
- POST /lesson-plan-templates/:id/create-plan deep-copies the template into a member plan
- Instantiation uses template name as default plan title, accepts custom title override
- Instantiation deactivates any existing active plan on the enrollment (one-active rule)
- Plan items are independent copies — renaming the template does not affect existing plans
- 11 new integration tests

packages/backend/src/db/migrations/0036_lesson_plan_templates.sql

@@ -0,0 +1,35 @@
+-- Phase 8: Lesson plan templates — reusable curriculum definitions
+
+CREATE TYPE "skill_level" AS ENUM ('beginner', 'intermediate', 'advanced', 'all_levels');
+
+CREATE TABLE "lesson_plan_template" (
+  "id" uuid PRIMARY KEY DEFAULT gen_random_uuid(),
+  "name" varchar(255) NOT NULL,
+  "description" text,
+  "instrument" varchar(100),
+  "skill_level" skill_level NOT NULL DEFAULT 'all_levels',
+  "created_by" uuid REFERENCES "user"("id"),
+  "is_active" boolean NOT NULL DEFAULT true,
+  "created_at" timestamptz NOT NULL DEFAULT now(),
+  "updated_at" timestamptz NOT NULL DEFAULT now()
+);
+
+CREATE TABLE "lesson_plan_template_section" (
+  "id" uuid PRIMARY KEY DEFAULT gen_random_uuid(),
+  "template_id" uuid NOT NULL REFERENCES "lesson_plan_template"("id"),
+  "title" varchar(255) NOT NULL,
+  "description" text,
+  "sort_order" integer NOT NULL,
+  "created_at" timestamptz NOT NULL DEFAULT now()
+);
+
+CREATE TABLE "lesson_plan_template_item" (
+  "id" uuid PRIMARY KEY DEFAULT gen_random_uuid(),
+  "section_id" uuid NOT NULL REFERENCES "lesson_plan_template_section"("id"),
+  "title" varchar(255) NOT NULL,
+  "description" text,
+  "grading_scale_id" uuid REFERENCES "grading_scale"("id"),
+  "target_grade_value" varchar(50),
+  "sort_order" integer NOT NULL,
+  "created_at" timestamptz NOT NULL DEFAULT now()
+);

packages/backend/src/db/migrations/meta/_journal.json

@@ -253,6 +253,13 @@
       "when": 1774950000000,
       "tag": "0035_grade_history",
       "breakpoints": true
+    },
+    {
+      "idx": 36,
+      "version": "7",
+      "when": 1774960000000,
+      "tag": "0036_lesson_plan_templates",
+      "breakpoints": true
     }
   ]
 }