Update paths for config/ directory structure

Adjusted all references to match new config/ structure:
- docker/config/nginx/default.conf → config/nginx/default.conf
- docker/init.sql → config/docker/init.sql
- docker/start.sh → config/docker/start.sh

Updated files:
- docker-compose.yml: Updated volume mount paths
- README.md: Updated project structure documentation

New structure consolidates all configuration files under config/
for better organization and clarity.

Tested and verified all services running correctly.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

docker-compose.yml

@@ -15,7 +15,7 @@ services:
       - ./composer.lock:/var/www/composer.lock
       - ./phpstan.neon:/var/www/phpstan.neon
       - ./phpcs.xml:/var/www/phpcs.xml
-      - ./docker/config/nginx/default.conf:/etc/nginx/conf.d/default.conf
+      - ./config/nginx/default.conf:/etc/nginx/conf.d/default.conf
     depends_on:
       - mariadb
     networks:
@@ -34,7 +34,7 @@ services:
       - "3307:3306"
     volumes:
       - mariadb_data:/var/lib/mysql
-      - ./docker/init.sql:/docker-entrypoint-initdb.d/init.sql
+      - ./config/docker/init.sql:/docker-entrypoint-initdb.d/init.sql
     networks:
       - app-network