feat: add Cloudron packaging templates

- Create Package-Templates directory structure
- Add official-wrapper Dockerfile template
- Add Django application template (Dockerfile + start.sh)
- Add README template with comprehensive documentation
- Create template usage documentation

Templates include:
- Official Image Wrapper pattern (simple wrapper for existing images)
- Django Application pattern (with PostgreSQL integration)
- Standardized README template with all sections
- Django start.sh with database wait, migrations, admin creation
- Template documentation and usage instructions

Benefits:
- Accelerates packaging for similar applications
- Ensures consistency across packages
- Reduces repetitive work
- Documents Cloudron best practices
- Reference for future packaging

Template patterns covered:
- Official image wrapper
- Django application with PostgreSQL
- Database wait logic
- Migration execution
- Admin user creation
- Health check implementation
- Environment variable configuration

💘 Generated with Crush

Assisted-by: GLM-4.7 via Crush <crush@charm.land>

Package-Templates/django-app/Dockerfile.template

@@ -0,0 +1,41 @@
+# Django Application Cloudron Package
+
+FROM python:3-slim
+
+# Install system dependencies
+RUN apt-get update && apt-get install -y --no-install-recommends \
+        curl \
+        gosu \
+        libpq-dev \
+        gcc \
+        postgresql-client \
+    && rm -rf /var/lib/apt/lists/*
+
+# Set working directory
+WORKDIR /app
+
+# Copy requirements
+COPY requirements.txt .
+
+# Install Python dependencies
+RUN pip install --no-cache-dir -r requirements.txt
+
+# Copy application code
+COPY . .
+
+# Copy start script (make it executable on host first!)
+COPY start.sh /app/start.sh
+RUN chmod +x /app/start.sh
+
+# Set environment
+ENV PYTHONUNBUFFERED=1
+
+# Expose port
+EXPOSE 8080
+
+# Health check
+HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
+    CMD curl -f http://localhost:8080/health/ || exit 1
+
+# Start Django application
+CMD ["/app/start.sh"]

Package-Templates/django-app/start.sh.template

@@ -0,0 +1,50 @@
+# Django Application Start Script Template
+
+#!/bin/bash
+
+set -e
+
+# Cloudron PostgreSQL connection
+DB_NAME=${CLOUDRON_POSTGRESQL_DATABASE:-app}
+DB_USER=${CLOUDRON_POSTGRESQL_USERNAME:-app}
+DB_PASSWORD=${CLOUDRON_POSTGRESQL_PASSWORD}
+DB_HOST=${CLOUDRON_POSTGRESQL_HOST:-127.0.0.1}
+DB_PORT=${CLOUDRON_POSTGRESQL_PORT:-5432}
+
+echo "Database host: $DB_HOST"
+echo "Database port: $DB_PORT"
+echo "Database name: $DB_NAME"
+
+# Django configuration
+export DJANGO_SETTINGS_MODULE=${DJANGO_SETTINGS_MODULE:-config.production}
+export SECRET_KEY=${SECRET_KEY:-cloudron-secret-key-change-in-production}
+export ALLOWED_HOSTS=${ALLOWED_HOSTS:-'*'}
+export DATABASE_URL=postgres://${DB_USER}:${DB_PASSWORD}@${DB_HOST}:${DB_PORT}/${DB_NAME}
+
+# Wait for PostgreSQL to be ready
+echo "Waiting for PostgreSQL to be ready..."
+until PGPASSWORD=$DB_PASSWORD psql -h "$DB_HOST" -p "$DB_PORT" -U "$DB_USER" -d "$DB_NAME" -c '\q' 2>/dev/null; do
+  echo "PostgreSQL is unavailable - sleeping"
+  sleep 2
+done
+
+echo "PostgreSQL is ready!"
+
+# Run Django migrations
+echo "Running Django migrations..."
+python manage.py migrate --noinput
+
+# Collect static files
+echo "Collecting static files..."
+python manage.py collectstatic --noinput
+
+# Create admin user if specified
+if [ -n "$ADMIN_USERNAME" ] && [ -n "$ADMIN_PASSWORD" ] && [ -n "$ADMIN_EMAIL" ]; then
+  echo "Creating admin user..."
+  echo "from django.contrib.auth import get_user_model; from django.core.management import call_command; User = get_user_model(); User.objects.create_superuser('$ADMIN_USERNAME', '$ADMIN_EMAIL', '$ADMIN_PASSWORD') if not User.objects.filter(email='$ADMIN_EMAIL').exists() else None" | \
+    python manage.py shell 2>/dev/null || echo "Admin user may already exist"
+fi
+
+# Start Django application
+echo "Starting Django application..."
+exec gunicorn config.wsgi:application --bind 0.0.0.0:8080 --workers ${NUM_WORKERS:-4}