chore: Add Docker Hub deployment workflow plan

[Louisp78]

Summary

This PR adds a comprehensive plan for redesigning the deployment workflow to use Docker Hub instead of building Docker images directly on the VPS.

Changes

• 📋 Added docs/deployment-workflow-plan.md - Complete implementation plan for Docker Hub deployment

Key Improvements Planned

Current workflow: GitHub PR → SSH to VPS → git pull + docker build (resource-intensive)

Proposed workflow: GitHub PR → CI builds images → Push to Docker Hub → VPS pulls and deploys

Benefits

• Reduced VPS resource usage - No more building heavy images on the VPS
• Faster deployments - Pre-built images just need to be pulled
• Better CI/CD - Build happens in GitHub Actions with caching
• Cleaner VPS - Only needs docker-compose and configs, not source code

Implementation Roadmap

The plan document outlines:

1. Setting up Docker Hub secrets in GitHub
2. Rewriting the CI workflow to build and push images
3. Updating docker-compose.yml to use remote images
4. Simplifying the deploy.sh script
5. Verification steps

Next Steps

This is a planning document. The actual implementation will follow in subsequent PRs as outlined in the plan.

Files Modified

• docs/deployment-workflow-plan.md (new)