Add missing app files and fix Docker configuration

- Add all PHP app files (controllers, middleware, providers, models, enums)
  that were previously gitignored via app/.gitignore wildcard
- Fix app/.gitignore to no longer ignore all files
- Fix docker-compose.yml: use named volume for postgres to avoid chown permission errors on server
- Fix Dockerfile: use --classmap-authoritative for composer dump-autoload

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

_docker/app/Dockerfile

@@ -52,7 +52,7 @@ RUN composer install \
       --no-autoloader \
       --prefer-dist
 
-RUN composer dump-autoload --no-scripts --optimize && \
+RUN composer dump-autoload --no-scripts --optimize --classmap-authoritative && \
     chown -R root:www-data /var/www && \
     chmod 755 -R /var/www && \
     chmod -R 775 /var/www/bootstrap/cache