chore: add Dockerfile for containerized stdio server

Dockerfile

@@ -0,0 +1,33 @@
+# Backtrader MCP — local stdio MCP server
+#
+# The server speaks MCP over stdio. Hosts that launch containers for stdio
+# servers must run with `-i` (interactive stdin) and pipe JSON-RPC frames.
+#
+#   docker build -t backtrader-mcp .
+#   docker run -i --rm \
+#     -e BACKTRADER_MCP_STATE_ROOT=/state \
+#     -e BACKTRADER_MCP_SOURCE_ROOTS='{"market_data":"/data"}' \
+#     -e BACKTRADER_MCP_TARGET_ROOTS='{"strategies":"/generated"}' \
+#     -e BACKTRADER_MCP_RUNTIMES='{"default":"/runtime/backtrader"}' \
+#     -v "$(pwd)/state:/state" -v "$(pwd)/data:/data:ro" \
+#     -v "$(pwd)/generated:/generated" \
+#     backtrader-mcp serve
+#
+# The default runtime is the pinned CloudQuant Backtrader fork installed into
+# the image; mount your own checkout into BACKTRADER_MCP_RUNTIMES to override.
+
+FROM python:3.11-slim
+
+WORKDIR /app
+
+COPY pyproject.toml README.md LICENSE ./
+COPY src ./src
+
+RUN pip install --no-cache-dir .
+
+ENV BACKTRADER_MCP_STATE_ROOT=/var/lib/backtrader-mcp/state
+
+VOLUME ["/var/lib/backtrader-mcp/state"]
+
+ENTRYPOINT ["backtrader-mcp"]
+CMD ["serve"]