feat: add Docker setup exposing app on port 7876
- Dockerfile: php:apache base, installs PHP extensions + Composer,
configures Apache to listen on port 7876, bundles app code,
runs composer install at build time
- docker-compose.yml: web service (port 7876) + MariaDB LTS with
healthcheck; writable volume for DB persistence
- docker/entrypoint.sh: generates .env from environment variables
at container start, fixes runtime permissions
- docker/php.ini: tuned PHP limits (512M memory, 32M upload)
- .dockerignore: excludes .git, vendor, logs, cache, old docker dir
- .env.example: template for required environment variables
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>