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>

docker-compose.prod.yml

@@ -0,0 +1,65 @@
+###############################################################################
+# eCert MBIP — Docker Compose Production Overrides (Ubuntu Server)
+#
+# Penggunaan:
+#   docker compose -f docker-compose.yml -f docker-compose.prod.yml up -d --build
+#
+# Perbezaan dari dev:
+#   • APP_ENV=production, APP_DEBUG=false
+#   • DB port TIDAK didedahkan ke host
+#   • Storage sijil/template disimpan dalam named volume (kekal semasa deploy)
+#   • Opcache validate_timestamps=0 (prestasi)
+#   • php-dev.ini tidak dimuat
+###############################################################################
+name: ecert
+
+services:
+
+  # ── PHP-FPM Application (production) ──────────────────────────────────────
+  app:
+    container_name: ecert_app
+    restart: always
+    volumes:
+      # Kod dari server (git pull)
+      - .:/var/www
+      # php.ini sahaja (tanpa php-dev.ini)
+      - ./docker/php/php.ini:/usr/local/etc/php/conf.d/99-ecert.ini:ro
+      # Storage kekal semasa redeploy
+      - storage_data:/var/www/storage
+    environment:
+      APP_ENV:   production
+      APP_DEBUG: "false"
+
+  # ── Nginx (production) ─────────────────────────────────────────────────────
+  nginx:
+    container_name: ecert_nginx
+    restart: always
+    volumes:
+      - .:/var/www:ro
+      - ./docker/nginx/default.conf:/etc/nginx/conf.d/default.conf:ro
+      # Mount storage supaya nginx boleh serve fail statik jika perlu
+      - storage_data:/var/www/storage:ro
+
+  # ── MySQL (production) ─────────────────────────────────────────────────────
+  db:
+    container_name: ecert_db
+    restart: always
+    ports: []    # Jangan dedahkan DB port ke luar dalam production
+    volumes:
+      - dbdata:/var/lib/mysql
+
+  # ── Queue Worker (production) ──────────────────────────────────────────────
+  queue:
+    container_name: ecert_queue
+    restart: always
+    volumes:
+      - .:/var/www
+      - ./docker/php/php.ini:/usr/local/etc/php/conf.d/99-ecert.ini:ro
+      - storage_data:/var/www/storage
+    environment:
+      APP_ENV: production
+
+###############################################################################
+volumes:
+  storage_data:
+    driver: local