Initial commit: LMS microservices scaffold

- Gradle multi-module: libs/{common-http,security-jwt,markdown,test-support},
  services/{identity,academic,progress,gateway}, web (Thymeleaf+htmx)
- identity-service: JWT auth (RSA), accounts, students, groups, enrollment,
  import from XLSX/CSV, credentials export, password reset
- academic-service: lab import from JSON/zip (markdown + YAML + variants),
  levels, API
- progress-service: schema for student levels and variant assignments
- gateway: Spring Cloud Gateway, JWT validation, route propagation
- web: Server-side UI with flex/footer layout, light/dark theme toggle,
  admin dashboard, groups CRUD, student portal placeholder
- docker-compose: PostgreSQL 18
- Tests: identity smoke test with Testcontainers

.env.example

@@ -0,0 +1,8 @@
+# Copy to .env and adjust for your environment.
+LMS_DB_NAME=lms
+LMS_DB_USER=lms
+LMS_DB_PASSWORD=lms
+LMS_DB_PORT=5432
+
+# JDBC connection string shared by the services (schema is selected per service).
+LMS_DB_URL=jdbc:postgresql://localhost:5432/lms