feat: Docker Compose setup untuk development & production

- docker/php/Dockerfile: PHP 8.4-FPM + GD + imagick (PECL) + semua extension Laravel
- docker/php/php.ini: upload 20MB, memory 512MB, opcache, Asia/Kuala_Lumpur
- docker/php/php-dev.ini: validate_timestamps=1, display_errors=On (dev)
- docker/nginx/default.conf: gzip, security headers, static asset caching
- docker/entrypoint.sh: tunggu MySQL → migrate → seed AdminSeeder → cache (prod)
- docker-compose.yml: dev stack — port 8003, DB host 33060, queue worker
- docker-compose.prod.yml: production overrides — storage volume, no DB port exposed
- .env.docker: template env untuk Docker (DB_HOST=db)
- .dockerignore: exclude node_modules, vendor, .env, logs

fix: testGenerate try/catch kembalikan JSON error (bukan HTML 500)
fix: loadPreview() semak r.ok, tunjuk error alert, loading spinner

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.dockerignore

@@ -0,0 +1,48 @@
+# ──────────────────────────────────────────────────────────────────────────────
+# .dockerignore — fail yang TIDAK disertakan dalam Docker build context
+# ──────────────────────────────────────────────────────────────────────────────
+
+# Git
+.git
+.gitignore
+.gitattributes
+
+# Dependencies (akan dipasang semula dalam container)
+node_modules
+vendor
+
+# Environment secrets
+.env
+.env.*
+!.env.docker
+!.env.example
+
+# Build output (akan dihasilkan semula)
+public/hot
+public/build
+
+# Dev tools
+.idea
+.vscode
+*.code-workspace
+.editorconfig
+.phpunit.cache
+phpunit.xml
+
+# Docker files (tidak perlu dalam app container)
+docker-compose*.yml
+docker/
+
+# Logs & cache
+storage/logs/*
+storage/framework/cache/*
+storage/framework/sessions/*
+storage/framework/views/*
+bootstrap/cache/*
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Tests
+tests/