feat: ShellMate - SSH Chess TUI

Play chess in your terminal over SSH. No installs, no accounts.

Features:
- Beautiful terminal-filling chess board with ANSI colors
- Play against Stockfish AI (multiple difficulty levels)
- Two-step move interaction with visual feedback
- Leaderboard with PostgreSQL persistence
- SSH key persistence across restarts

Infrastructure:
- Docker containerized deployment
- CI/CD pipeline for dev/staging/production
- Health checks with auto-rollback
- Landing page at shellmate.sh

Tech: Python 3.12+, asyncssh, python-chess, Stockfish

Dockerfile

@@ -0,0 +1,29 @@
+FROM python:3.12-slim
+
+# Install Stockfish
+RUN apt-get update && apt-get install -y \
+    stockfish \
+    openssh-client \
+    && rm -rf /var/lib/apt/lists/*
+
+WORKDIR /app
+
+# Copy everything needed for install
+COPY pyproject.toml README.md ./
+COPY src/ src/
+
+# Install Python dependencies
+RUN pip install --no-cache-dir .
+
+# Create user and directories
+RUN useradd -m shellmate && \
+    mkdir -p /etc/shellmate && \
+    chown shellmate:shellmate /etc/shellmate
+
+EXPOSE 22
+
+# Key is generated at runtime (see entrypoint) or mounted from volume
+
+ENV STOCKFISH_PATH=/usr/games/stockfish
+
+CMD ["shellmate-server"]