feat(dev): add containerized development environment

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

dev/sandbox/Dockerfile

@@ -0,0 +1,34 @@
+FROM ubuntu:22.04
+
+# Prevent interactive prompts during package installation
+ENV DEBIAN_FRONTEND=noninteractive
+
+# Install common development tools and runtimes
+# - Node.js: Install v20 (LTS) from NodeSource
+# - Core: curl, git, vim, build-essential (gcc, make)
+# - Python: python3, pip
+# - Network: ping, dnsutils
+RUN apt-get update && apt-get install -y curl && \
+    curl -fsSL https://deb.nodesource.com/setup_20.x | bash - && \
+    apt-get install -y \
+    nodejs \
+    wget git vim nano unzip zip \
+    build-essential \
+    python3 python3-pip \
+    sudo \
+    iputils-ping dnsutils net-tools \
+    && rm -rf /var/lib/apt/lists/* \
+    && node --version && npm --version
+
+# Create a non-root user 'developer' with UID 1000
+# Grant passwordless sudo to simulate a local dev environment (using safe sudoers.d)
+RUN useradd -m -s /bin/bash -u 1000 developer && \
+    echo "developer ALL=(ALL) NOPASSWD:ALL" > /etc/sudoers.d/developer && \
+    chmod 0440 /etc/sudoers.d/developer
+
+# Set up the workspace
+USER developer
+WORKDIR /home/developer/workspace
+
+# Default command
+CMD ["/bin/bash"]