fix CONTRIBUTING.md: branch naming should include issue number

Address han's review feedback:
- Changed feat/feature-name to feat/issue-N-feature-name
- Consistent with fix/issue-N-name format

CONTRIBUTING.md

@@ -2,7 +2,7 @@
 
 ## Workflow
 
-1. Create a branch for your work: `git checkout -b fix/issue-N-name` or `git checkout -b feat/feature-name`
+1. Create a branch for your work: `git checkout -b fix/issue-N-name` or `git checkout -b feat/issue-N-feature-name`
 2. Make changes and commit with clear messages
 3. Open a Pull Request for review
 4. Do not merge directly to `main` or `develop` for reviewable changes