feat: add gamification features for users, including XP and leveling, with corresponding database schema and API response updates.

services/lms-service/migrations/20251231000000_add_gamification_to_users.sql

@@ -0,0 +1,3 @@
+-- Add xp and level to users table
+ALTER TABLE users ADD COLUMN IF NOT EXISTS xp INT NOT NULL DEFAULT 0;
+ALTER TABLE users ADD COLUMN IF NOT EXISTS level INT NOT NULL DEFAULT 1;