Fix entrypoint: create .env file for key generation in Docker

CapRover injects env vars via Docker, not a .env file. The key:generate
command needs the file to exist to write the generated key.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docker/entrypoint.sh

@@ -7,8 +7,15 @@ mkdir -p storage/framework/{cache/data,sessions,views} storage/logs bootstrap/ca
 chown -R www-data:www-data storage bootstrap/cache
 chmod -R 775 storage bootstrap/cache
 
-if [ -z "$APP_KEY" ]; then
+# Create .env from environment variables if it doesn't exist
+if [ ! -f .env ]; then
+    echo "APP_KEY=" > .env
+fi
+
+# Generate APP_KEY if not set
+if [ -z "$APP_KEY" ] || [ "$APP_KEY" = "" ]; then
     php artisan key:generate --force --no-interaction
+    export APP_KEY=$(grep '^APP_KEY=' .env | cut -d= -f2-)
 fi
 
 php artisan config:cache