Improve CI/CD between `dev` and `main` branch

[helen-m-lin]

Is your feature request related to a problem? Please describe. As a developer, I want to automate or improve the prod deployment process, so I can ensure smooth deployments and avoid manual mistakes.

• Currently, production deployments are triggered when changes are made to the main branch, while test deployments are triggered by changes to the dev branch
• To deploy to prod, we create a PR from dev to main, while requires intermediate steps of first merging main into dev and resolving merge conflicts.
• Additionally, the previous commit history is merged again on every merge to main

Describe the solution you'd like We should implement a solution to bridge the dev-main deployment process and keep dev/ main in sync after prod deployment. We should have a solution such that:

• no new branch can be created from main
• no commits can be directly made in main or dev
• main should only accept pull requests from dev
• PR from dev to main should not have merge conflicts
• dev should remain as the default branch
• test deployments should continue to be triggered from changes to dev
• production deployments should continue to be triggered from changes to main

Describe alternatives you've considered A clear and concise description of any alternative solutions or features you've considered.

Additional context Add any other context or screenshots about the feature request here.