feat: implement structured grading system with predefined assessment types

- Add structured grading policy with predefined types (Continuous Assessment, Midterm, Final Test, Exam)
- Replace free-text category input with combobox selection in Grading Policy page
- Update Lesson Editor to use dropdown selector for grading category assignment
- Fix create_grading_category handler to capture organization context
- Fix update_course handler to set audit context in database transaction
- Implement getImageUrl helper for proper asset path resolution
- Add unoptimized prop to organization logo images to bypass Next.js optimization
- Add database migrations for organization_id in content tables
- Seed default tutorial courses for Admin, Instructor, and Student roles
- Fix audit log constraints and content schema issues

services/cms-service/migrations/20260111000008_fix_content_schema_final.sql

@@ -0,0 +1,28 @@
+-- Migration: Final Content Schema Alignment
+-- Scope: lessons, modules
+
+-- 1. Add missing columns to lessons
+ALTER TABLE lessons ADD COLUMN IF NOT EXISTS content_blocks JSONB DEFAULT '[]';
+ALTER TABLE lessons ADD COLUMN IF NOT EXISTS updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW();
+
+-- 2. Add missing columns to modules
+ALTER TABLE modules ADD COLUMN IF NOT EXISTS updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW();
+
+-- 3. Create Update Trigger for updated_at (if not already exists)
+-- Function update_updated_at_column was defined in initial_schema.sql
+
+-- Attach triggers to lessons and modules
+DO $$
+BEGIN
+    IF NOT EXISTS (SELECT 1 FROM pg_trigger WHERE tgname = 'trg_lessons_updated_at') THEN
+        CREATE TRIGGER trg_lessons_updated_at
+        BEFORE UPDATE ON lessons
+        FOR EACH ROW EXECUTE FUNCTION update_updated_at_column();
+    END IF;
+
+    IF NOT EXISTS (SELECT 1 FROM pg_trigger WHERE tgname = 'trg_modules_updated_at') THEN
+        CREATE TRIGGER trg_modules_updated_at
+        BEFORE UPDATE ON modules
+        FOR EACH ROW EXECUTE FUNCTION update_updated_at_column();
+    END IF;
+END $$;