Add troubleshooting section to README (#5019)

* Add troubleshooting section to README

* Move developer troubleshooting from README to Docs

Author: omrajshinde534

Docs/troubleshooting.md

@@ -0,0 +1,98 @@
+# Developer Troubleshooting
+
+This document contains developer-focused troubleshooting guidance for building,
+running, and contributing to Music Blocks. End users should refer to the main
+README and user documentation.
+
+## Browser Shows Blank Page or Blocks Not Displaying
+
+Problem:
+The application loads but shows a blank screen or blocks do not appear.
+
+Solution:
+1. Open the browser Developer Tools.
+   - Chrome / Edge: F12 or Ctrl + Shift + J
+   - Firefox: Ctrl + Shift + K
+2. Check the Console tab for JavaScript errors.
+3. Fix the reported errors and reload the page.
+4. Try running the app in Chrome or Firefox if the issue persists.
+
+## npm install Fails with Permission Errors
+
+Problem:
+Dependency installation fails due to permission issues or corrupted files.
+
+Solution:
+Run the following commands from the project root:
+
+rm -rf node_modules package-lock.json  
+npm install
+
+On Windows, use PowerShell or Git Bash.
+
+## npm run lint Fails with Formatting Errors
+
+Problem:
+Linting errors block the build due to formatting issues.
+
+Solution:
+Run Prettier first, then re-run lint:
+
+npx prettier --write .  
+npm run lint
+
+## Docker Container Won’t Start
+
+Problem:
+Docker build fails or the container does not start correctly.
+
+Solution:
+Clean Docker state and rebuild:
+
+docker system prune  
+docker-compose up --build
+
+## Port Already in Use (EADDRINUSE)
+
+Problem:
+The development server fails to start because port 3000 is already in use.
+
+Solution:
+Start the server on a different port:
+
+npm start -- --port=3001
+
+Then open http://localhost:3001 in your browser.
+
+## No Sound / Audio Not Working
+
+Problem:
+The application runs but produces no sound.
+
+Solution:
+1. Ensure system volume is not muted.
+2. Check browser audio permissions.
+3. Click once anywhere on the page to enable audio playback.
+4. Use a supported browser (Chrome or Firefox recommended).
+
+## Module Not Found Errors
+
+Problem:
+Errors such as "Cannot find module" appear during runtime or build.
+
+Solution:
+Reinstall dependencies:
+
+rm -rf node_modules package-lock.json  
+npm install
+
+## Still Having Issues?
+
+If problems persist:
+1. Search existing GitHub issues:
+   https://github.com/sugarlabs/musicblocks/issues
+2. Review developer documentation.
+3. Open a new issue with:
+   - Error logs
+   - Steps to reproduce
+   - Browser and OS details