feat(docker): add Docker support with multi-platform builds

[offendingcommit]

Summary

This PR transforms this repository into a Docker-focused distribution of mcp-remote, providing:

• Pre-built multi-platform Docker images on ghcr.io
• Comprehensive Docker documentation
• Easy integration with MCP clients using Docker

Changes

Docker Infrastructure

• Dockerfile: Multi-stage build with Node 22 Alpine, runs as non-root user
• docker-compose.yml: Easy container management with volume mounting
• GitHub Actions: Automated multi-platform builds (linux/amd64, linux/arm64) and publishing to ghcr.io
• .dockerignore: Optimized build context

Documentation Refactor

• README.md: Now Docker-focused with examples for all MCP clients
• README.Docker.md: Detailed Docker usage guide
• README.npm.md: Preserved npm documentation for reference
• CLAUDE.md: Added Docker commands section

Workflow Updates

• Removed npm publish workflow (not needed for Docker distribution)
• Enhanced Docker workflow with detailed documentation
• Maintained code quality checks (prettier, TypeScript)

Test Results

• Build Docker image locally
• Test running proxy in container
• Test OAuth flow with port forwarding (verified container runs and attempts connection)
• Verify multi-platform builds in CI (confirmed linux/amd64 and linux/arm64)
• Confirm images publish to ghcr.io on merge (workflow configured correctly)

Docker Usage

# Using pre-built images
docker pull ghcr.io/offendingcommit/mcp-remote:latest
docker run -it ghcr.io/offendingcommit/mcp-remote:latest https://your-server/sse

# With persistent OAuth tokens
docker run -it -v mcp-auth:/home/mcp/.mcp-auth ghcr.io/offendingcommit/mcp-remote:latest https://your-server/sse

Ready for review and merge!