Add Contribution Guidelines `CONTRIBUTING.md`

Create a well-structured CONTRIBUTING.md file to establish clear contribution guidelines. This should enforce a standardized branch workflow and ensure that all contributors follow the Commitizen convention for commit messages.

Branch Workflow Guidelines

The contributing guide should include the following branching strategy to maintain a clean and organized repository:

main → Production-ready code. Do not push directly.
dev → All features and bug fixes should be merged and tested here before being pushed to main.
feat/feature-name → New feature branches (e.g., feat/user-auth).
fix/bug-description → Bug fix branches (e.g., fix/navbar-issue).
hotfix/critical-bug-name → Critical production bug fixes (e.g., hotfix/payment-error).
refactor/module-name → Code improvements and optimizations (e.g., refactor/api-cleanup).

Commit Message Standard (Commitizen Enforcement)

• Ensure Commitizen is enforced across the repo.
• Contributors must use git cz instead of git commit to maintain a consistent commit format.