Add GitHub Actions workflow to build and publish Docker image

[jacepark12]

Description

Should set up a GitHub Actions workflow that automatically builds and publishes the MCP server as a Docker image to GHCR on each push to main or version tags.

Sub Tasks

• Create .github/workflows/docker-build.yml
• Configure Docker login using secrets
• Set up image build and push on main/tag push
• Update README with Docker usage instructions

[JakobGruen]

Hi! 👋

Check out my PR #34 - I've implemented the tasks in this issue in my latest commits.

✅ Completed Sub Tasks:

• Create docker-build.yml - Added workflow that builds and pushes to GHCR
• Configure Docker login using secrets - Uses GITHUB_TOKEN with proper permissions
• Set up image build and push on main/tag push - Triggers on both main pushes and version tags
• Update README with Docker usage instructions - Added comprehensive Docker section with examples

🚀 Additional Features in the PR:

The PR also implements HTTP transport support for the MCP server, which enables:

• Running the server over HTTP instead of just stdio
• Better compatibility with containerized environments
• Web-based access to the MCP server

⚠️ Current Limitations:

• The Docker implementation currently only supports HTTP transport mode. I haven't figured out how to properly implement stdio transport with Docker containers - if anyone has ideas on that, I'd love to hear them!
• When running the authentication, the environment variables have to be set in the .env file before building or manually entered. It doesn't support docker run -e [ENV_VAR] [IMAGE] or docker run -env-file .env [IMAGE]. This comes from the way the environment is loaded in authenticate.py

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Would appreciate any feedback on the implementation! 🙂