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/php/Dockerfile

@@ -0,0 +1,70 @@
+###############################################################################
+# eCert MBIP — PHP-FPM Runtime Image
+# PHP 8.4 + GD + imagick + semua extension Laravel
+###############################################################################
+FROM php:8.4-fpm
+
+LABEL org.opencontainers.image.title="eCert MBIP" \
+      org.opencontainers.image.description="Sistem Pengurusan Sijil Digital MBIP"
+
+# ── System libraries ──────────────────────────────────────────────────────────
+RUN apt-get update && apt-get install -y --no-install-recommends \
+        git \
+        curl \
+        zip \
+        unzip \
+        # zip extension
+        libzip-dev \
+        # GD: PNG, JPEG, WebP, FreeType
+        libpng-dev \
+        libjpeg62-turbo-dev \
+        libfreetype6-dev \
+        libwebp-dev \
+        # mbstring
+        libonig-dev \
+        # xml / intl
+        libxml2-dev \
+        libicu-dev \
+        # imagick
+        libmagickwand-dev \
+        # mysql client (wait-for-db in entrypoint)
+        default-mysql-client \
+    && rm -rf /var/lib/apt/lists/*
+
+# ── GD (untuk Intervention Image — GD driver) ─────────────────────────────────
+RUN docker-php-ext-configure gd \
+        --with-freetype \
+        --with-jpeg \
+        --with-webp \
+    && docker-php-ext-install -j$(nproc) gd
+
+# ── Core PHP extensions ───────────────────────────────────────────────────────
+RUN docker-php-ext-install -j$(nproc) \
+        pdo_mysql \
+        mbstring \
+        exif \
+        pcntl \
+        bcmath \
+        zip \
+        intl \
+        opcache
+
+# ── imagick (PECL) — tersedia sebagai driver alternatif ───────────────────────
+RUN pecl install imagick \
+    && docker-php-ext-enable imagick \
+    && rm -rf /tmp/pear
+
+# ── Composer ──────────────────────────────────────────────────────────────────
+COPY --from=composer:2 /usr/bin/composer /usr/bin/composer
+
+# ── Working directory ─────────────────────────────────────────────────────────
+WORKDIR /var/www
+
+# ── Entrypoint ────────────────────────────────────────────────────────────────
+COPY docker/entrypoint.sh /usr/local/bin/entrypoint.sh
+RUN chmod +x /usr/local/bin/entrypoint.sh
+
+EXPOSE 9000
+
+ENTRYPOINT ["entrypoint.sh"]
+CMD ["php-fpm"]