fix(Dockerfile): install libbrotli for swoole pecl build

Swoole 6.x enables brotli compression by default and requires
libbrotli-dev at build time + brotli-libs at runtime. Without them the
configure step fails with "Package 'libbrotlienc' not found".

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: abnegate

Dockerfile

@@ -23,10 +23,11 @@ RUN apk add --no-cache --virtual .build-deps \
         $PHPIZE_DEPS \
         linux-headers \
         openssl-dev \
+        brotli-dev \
     && pecl install swoole \
     && docker-php-ext-enable swoole \
     && apk del .build-deps \
-    && apk add --no-cache libstdc++
+    && apk add --no-cache libstdc++ brotli-libs
 
 COPY --from=composer /usr/local/src/vendor /usr/local/src/vendor
 COPY . /usr/local/src/