fix : resolve Docker port conflicts and fix var/ permissions on install

Port PG 5436→5437, port frontend 3003→3005 to avoid conflicts with Coltura.
Add fix-permissions target in Makefile to create var/cache and var/log as root before composer install.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

infra/dev/Dockerfile

@@ -81,7 +81,7 @@ RUN mkdir -p /var/www/.composer/cache/vcs \
 ENV COMPOSER_HOME=/var/www/.composer
 
 # Création de la structure du projet
-RUN mkdir /var/www/html/LOG
+RUN mkdir -p /var/www/html/LOG /var/www/html/var/cache /var/www/html/var/log
 
 ###> User ###
 ARG CURRENT_UID