Remove linux-libc-dev from devcontainer image to mitigate Trivy CVE-2026-31431 finding (#35)

* fix: remove explicit linux-libc-dev install from devcontainer

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Co-authored-by: idvoretskyi <118459+idvoretskyi@users.noreply.github.com>

* fix: purge inherited linux-libc-dev from devcontainer image

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Co-authored-by: idvoretskyi <118459+idvoretskyi@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: idvoretskyi <118459+idvoretskyi@users.noreply.github.com>

Author: Copilot

.devcontainer/Dockerfile

@@ -7,8 +7,9 @@ RUN apt-get update && export DEBIAN_FRONTEND=noninteractive \
     python3-venv \
     python3-pip \
     sudo \
-    linux-libc-dev \
     vim-tiny \
     && apt-get -y upgrade \
+    && apt-get -y purge linux-libc-dev \
+    && apt-get -y autoremove \
     && apt-get clean \
     && rm -rf /var/lib/apt/lists/*