feat: [CI] Setup Docker Build & Push Pipeline for Microservices

[parth5012]

📌 Description

This PR implements the Continuous Integration (CI) pipeline requested in #41 to automate the containerization of the MicroForge application.

What does this PR do?

• Added Root Dockerfile: Created a comprehensive Multi-Stage Dockerfile that defines build targets for all 5 microservices (auth, frontend, login, metadata, notification).
• GitHub Actions Workflow: Implemented .github/workflows/docker-publish.yml using a Matrix Strategy. This allows all 5 services to be built and pushed in parallel jobs.
• Dynamic Tagging: Configured the pipeline to tag images with semantic versions (e.g., v1.0.0), latest, and the Git commit SHA for traceability.

Why is this change needed?
Previously, builds and pushes were manual. This automation ensures that every change to the master branch is automatically verified, built, and deployed to the Docker Registry without human intervention.

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🔗 Related Issue

Fixes #41

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🛠️ Type of Change

Please mark the relevant option:

• Documentation update
• Bug fix
• New feature
• Refactor
• Configuration / DevOps change
• Other (please explain)

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🧪 How Was This Tested?

Describe how you verified your changes:

• Docker Compose runs successfully
• Frontend loads correctly
• Service builds without errors
• Documentation renders correctly
• Manual testing (Verified workflow execution on a fork/feature branch)

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📸 Screenshots (if applicable)

No UI changes. Workflow logs confirm successful parallel builds:

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✅ Checklist

Please confirm the following:

• My code follows the project structure
• I tested my changes locally (and via CI triggers)
• I linked the relevant issue
• I kept this PR focused and minimal
• I am open to feedback and changes

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📝 Additional Notes

⚠️ Critical Setup for Maintainers:

For this pipeline to function correctly after merging, the project admin must add the following Repository Secrets in Settings > Secrets and variables > Actions:

1. DOCKER_USERNAME: The Docker Hub username.
2. DOCKER_PASSWORD: The Docker Hub password (or Access Token).

[github-actions]

🚫 Pull Request Policy Violation

Hi @parth5012, thanks for your contribution!

Direct PRs to the master branch are not allowed. Please close this PR and target the stage branch instead for review.