Performance: OPcache, gzip, font subsetting, lazy-loaded pages

- Enable PHP OPcache in Docker (256MB, dev-friendly settings)
- Enable gzip compression in nginx + immutable caching for /build/ assets
- Reduce fonts to latin-only subsets (from 28 files to ~6)
- Lazy-load Vue pages via dynamic imports (D3 no longer loaded on login)
- MetroMap chunk split out separately (62KB only when needed)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docker/php/Dockerfile

@@ -28,6 +28,10 @@ RUN docker-php-ext-configure gd --with-freetype --with-jpeg \
 RUN pecl install redis \
     && docker-php-ext-enable redis
 
+# Enable OPcache
+RUN docker-php-ext-enable opcache
+COPY docker/php/opcache.ini /usr/local/etc/php/conf.d/opcache.ini
+
 # Install Composer
 COPY --from=composer:latest /usr/bin/composer /usr/bin/composer