feat: Add devcontainer configuration for n8n-workflows development

- Configure Claude Code optimized devcontainer with Python support
- Add Python development tools (black, flake8, isort) to Dockerfile
- Include VS Code extensions for Python and workflow development
- Add firewall script for secure development environment
- Update .gitignore to exclude Claude Code local settings

🤖 Generated with [Claude Code](https://claude.ai/code)

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

.devcontainer/Dockerfile

@@ -0,0 +1,87 @@
+FROM node:20
+
+ARG TZ
+ENV TZ="$TZ"
+
+# Install basic development tools, Python, and iptables/ipset
+RUN apt update && apt install -y less \
+  git \
+  procps \
+  sudo \
+  fzf \
+  zsh \
+  man-db \
+  unzip \
+  gnupg2 \
+  gh \
+  iptables \
+  ipset \
+  iproute2 \
+  dnsutils \
+  aggregate \
+  jq \
+  python3 \
+  python3-pip \
+  python3-venv \
+  python3-dev
+
+# Ensure default node user has access to /usr/local/share
+RUN mkdir -p /usr/local/share/npm-global && \
+  chown -R node:node /usr/local/share
+
+ARG USERNAME=node
+
+# Persist bash history.
+RUN SNIPPET="export PROMPT_COMMAND='history -a' && export HISTFILE=/commandhistory/.bash_history" \
+  && mkdir /commandhistory \
+  && touch /commandhistory/.bash_history \
+  && chown -R $USERNAME /commandhistory
+
+# Set `DEVCONTAINER` environment variable to help with orientation
+ENV DEVCONTAINER=true
+
+# Create workspace and config directories and set permissions
+RUN mkdir -p /workspace /home/node/.claude && \
+  chown -R node:node /workspace /home/node/.claude
+
+WORKDIR /workspace
+
+RUN ARCH=$(dpkg --print-architecture) && \
+  wget "https://github.com/dandavison/delta/releases/download/0.18.2/git-delta_0.18.2_${ARCH}.deb" && \
+  sudo dpkg -i "git-delta_0.18.2_${ARCH}.deb" && \
+  rm "git-delta_0.18.2_${ARCH}.deb"
+
+# Set up non-root user
+USER node
+
+# Install global packages
+ENV NPM_CONFIG_PREFIX=/usr/local/share/npm-global
+ENV PATH=$PATH:/usr/local/share/npm-global/bin
+
+# Set the default shell to zsh rather than sh
+ENV SHELL=/bin/zsh
+
+# Default powerline10k theme
+RUN sh -c "$(wget -O- https://github.com/deluan/zsh-in-docker/releases/download/v1.2.0/zsh-in-docker.sh)" -- \
+  -p git \
+  -p fzf \
+  -a "source /usr/share/doc/fzf/examples/key-bindings.zsh" \
+  -a "source /usr/share/doc/fzf/examples/completion.zsh" \
+  -a "export PROMPT_COMMAND='history -a' && export HISTFILE=/commandhistory/.bash_history" \
+  -x
+
+# Install Python packages and create symlink
+RUN pip3 install --upgrade pip && \
+  pip3 install black flake8 isort && \
+  ln -sf /usr/bin/python3 /usr/local/bin/python
+
+# Install Claude
+RUN npm install -g @anthropic-ai/claude-code
+
+# Copy and set up firewall script
+COPY init-firewall.sh /usr/local/bin/
+USER root
+RUN chmod +x /usr/local/bin/init-firewall.sh && \
+  echo "node ALL=(root) NOPASSWD: /usr/local/bin/init-firewall.sh" > /etc/sudoers.d/node-firewall && \
+  chmod 0440 /etc/sudoers.d/node-firewall
+USER node