Improve caching and error handling in hooks.server.js

[SophiaLi20]

This PR makes some improvements to hooks.server.js to optimize caching, improve error handling, and clean up the code for better readability.

Key Changes:

• Added cache expiration (5 minutes) to ensure we're not serving outdated route data.
• Improved error handling in fetchRoutesData() to log issues properly without breaking execution.
• Optimized performance by ensuring we only fetch new data when needed instead of on every request.
• Cleaned up the code with better comments, clearer variable names, and a more structured approach to handling agency data.

Why?

• Previously, routesCache was never refreshed, meaning the app could serve stale data indefinitely.
• handle() was calling preloadRoutesData() on every request, which wasn’t necessary.
• The code lacked comments and could be a bit tricky to follow at first glance.

Testing:

• Verified that routes are correctly cached and refreshed when needed.
• Checked that errors are logged properly without stopping execution.
• Ensured API calls are only made when required.

[CLAassistant]

All committers have signed the CLA.

[aaronbrethorst]

@SophiaLi20 please sign the CLA

[SophiaLi20]

Hey @aaronbrethorst , I have signed the CLA. Please let me know if any further action is required. Thanks!

[aaronbrethorst]

This looks great! Would you add a couple basic tests to the project to ensure that fetchRoutesData() works as expected?

[SophiaLi20]

Thanks, @aaronbrethorst ! I appreciate your feedback. I'll review your suggestions and make the necessary changes. Let me know if you have any specific concerns or if there's anything else you'd like me to address.

[SophiaLi20]

Hey @aaronbrethorst ,I sincerely apologize for the delay. I was occupied with exams and could not get to this sooner. I’ve added the requested tests for fetchRoutesData() and committed the changes. When you get a chance, could you take a look and let me know if any further modifications are needed? Happy to make any updates if needed. Thanks for your patience!