fix: add Dockerfile for Glama MCP directory listing

[ygd58]

Problem

The base-mcp server is listed on the Glama MCP directory but is not usable because it lacks a Dockerfile, as reported in #73.

Fix

Added a Dockerfile that:

• Uses node:22-alpine as base image
• Installs dependencies via npm ci
• Builds the TypeScript project via npm run build
• Runs the server via node build/index.js

Testing

npm install  ✅
npm run build  ✅

Closes #73