Set up PostgreSQL database configuration and enhance application structure

- Added .env.example with database connection details and JWT configuration.
- Introduced docker-compose.yml for PostgreSQL service setup with health checks.
- Created drizzle.config.ts for database schema and migration management.
- Updated nest-cli.json to include Swagger plugin configuration for API documentation.
- Enhanced package.json with new database-related scripts and dependencies.
- Implemented initial database migrations for user and token management.
- Configured application bootstrap process to load environment variables and set up Swagger.
- Added shared application configuration in configure-app.ts for consistent setup.
- Included unit tests for application configuration and Swagger setup.

.env.example

@@ -2,3 +2,24 @@
 # Stored values remain UTC unix milliseconds. Fixed offsets only (no IANA names).
 # Examples: GMT+7, GMT+07:00, UTC+7, +07:00, +7, +0700
 DEFAULT_TIMEZONE=GMT+7
+
+PORT=3000
+
+# PostgreSQL connection string (docker-compose default shown)
+DATABASE_URL=postgresql://tracking:tracking@localhost:5432/tracking
+
+# Required. Generate with: openssl rand -base64 48
+JWT_ACCESS_SECRET=
+
+# Access token lifetime (<number><s|m|h|d>)
+JWT_ACCESS_EXPIRES_IN=15m
+
+# Refresh token lifetime in milliseconds (default 7 days)
+REFRESH_TOKEN_EXPIRES_IN_MS=604800000
+
+# bcrypt cost factor
+BCRYPT_SALT_ROUNDS=10
+
+# OpenAPI UI at /docs (default: on unless NODE_ENV=production)
+# SWAGGER_ENABLED=true
+# SWAGGER_ENABLED=false