Fix Puma Dockerfile: install build-essential for nio4r native extension

The ruby:3.3-slim image lacks a C compiler, causing nio4r (a Puma
dependency) to fail during gem install. Install build-essential for
compilation then purge it to keep the image small.

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

Author: MDA2AV

src/Servers/PumaServer/Dockerfile

@@ -1,5 +1,8 @@
 FROM ruby:3.3-slim
-RUN gem install puma --no-doc
+RUN apt-get update && apt-get install -y --no-install-recommends build-essential && \
+    gem install puma --no-doc && \
+    apt-get purge -y build-essential && apt-get autoremove -y && \
+    rm -rf /var/lib/apt/lists/*
 COPY src/Servers/PumaServer/config.ru /app/config.ru
 WORKDIR /app
 EXPOSE 8080