feat: update Docker environment variables for database configuration

[Yehonal]

Refactor database configuration in the Docker setup to utilize environment variables for better flexibility and security.

[Copilot]

Pull Request Overview

Refactors the Docker Compose setup to pull database connection values from environment variables with sensible defaults.

• Switches fixed MySQL credentials to use ${VAR:-default} fallbacks
• Updates the WordPress service to reference the same DB vars
• Adds commented example entries for the new DB variables in .env.docker

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
docker-compose.yml	Replaced static MySQL/WordPress credentials with environment fallbacks
.env.docker	Added commented examples for new DOCKER_WORDPRESS_DB_* variables

Comments suppressed due to low confidence (1)

.env.docker:20

• [nitpick] Add a short note or update the project README to explain these new database environment variables and how to override them for different environments.

# DOCKER_WORDPRESS_DB_ROOT_PASSWORD=flkdsjalfh