chore(docker): ignore CI directories and use extension installer

- Add .github and .circleci to .dockerignore to reduce image size
- Replace docker-php-ext-install with mlocati's extension installer for better reliability and maintenance

.dockerignore

@@ -1,4 +1,6 @@
 .git
+.github
+.circleci
 .env
 node_modules
 vendor

Dockerfile

@@ -12,12 +12,15 @@ RUN apt-get update && apt-get install -y \
     libzip-dev \
     libicu-dev
 
+# Install PHP extensions installer
+ADD https://github.com/mlocati/docker-php-extension-installer/releases/latest/download/install-php-extensions /usr/local/bin/
+
+RUN chmod +x /usr/local/bin/install-php-extensions && \
+    install-php-extensions pdo_mysql mbstring exif pcntl bcmath gd zip intl
+
 # Clear cache
 RUN apt-get clean && rm -rf /var/lib/apt/lists/*
 
-# Install PHP extensions
-RUN docker-php-ext-install pdo_mysql mbstring exif pcntl bcmath gd zip intl
-
 # Get latest Composer
 COPY --from=composer:latest /usr/bin/composer /usr/bin/composer