CI: fix PHP version compatibility and add GD extension

Use php:8.3-cli instead of composer:latest to ensure PHP version compatibility (8.1-8.4 required). Install GD extension and required system dependencies for image manipulation packages.

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

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

.forgejo/workflows/deploy.yml

@@ -10,13 +10,29 @@ jobs:
     name: Deploy to Production
     runs-on: docker
     container:
-      image: composer:latest
+      image: php:8.3-cli
     steps:
       - name: Checkout code
         run: |
           git clone --depth 1 --branch main https://forge.studio-variable.com/${{ github.repository }}.git .
           ls -la
 
+      - name: Install system dependencies and PHP extensions
+        run: |
+          apt-get update && apt-get install -y --no-install-recommends \
+            libfreetype6-dev \
+            libjpeg62-turbo-dev \
+            libpng-dev \
+            unzip \
+            git \
+          && docker-php-ext-configure gd --with-freetype --with-jpeg \
+          && docker-php-ext-install -j$(nproc) gd \
+          && rm -rf /var/lib/apt/lists/*
+
+      - name: Install Composer
+        run: |
+          curl -sS https://getcomposer.org/installer | php -- --install-dir=/usr/local/bin --filename=composer
+
       - name: Install dependencies
         run: |
           composer install --no-dev --optimize-autoloader