feat: add Docker Compose setup for Coolify deployment

- Dockerfile: php:8.2-apache with pdo_mysql, curl, mod_rewrite
- docker-compose.yml: app + MySQL 8.0, healthchecks, named volumes
- .dockerignore: exclude .env, .git, uploads, docs
- .gitignore: add .env

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.dockerignore

@@ -0,0 +1,8 @@
+.env
+.git
+uploads/*
+!uploads/.gitkeep
+docs/
+*.md
+localguide-DESIGN.md
+COOLIFY_DOCKER_COMPOSE_KNOWLEDGE.md