feat #655: implements an error handling system with custom errors

[suzuhe481]

Description

Before:

Backend routes/functions were thrown or returned without always being caught.

After:

• Adds custom error classes to define specific error types with the file located in lib/errors/CustomErrors.ts.
  • BackendError, OpenAiError, SupabaseError, GoogleError
• Errors will only be logged at the top level of where a function/route was called. Will typically be right before a response is sent to the client. Normally, this is the catch block inside of a route.ts.
• Errors created/caught in nested functions will be continuously thrown until it gets caught in a catch block.
  • eg. The generateAndStoreSuggestions() function throws an OpenAiError, which gets rethrown in drawGiftExchange(), rethrown again in processGiftExchanges(), then finally caught and logged in a route.ts.
• Some functions didn't need to return anything, but still returned a success: boolean. I removed these returns, but errors will still be thrown.
• Added a logError(error: unknown) function located in lib/errors/logError.ts. This function is accepts the error to correctly identify and log it, as well as being easily expandable to new error types if they get created.

Closes #655

Screenshots

Example of error log in the terminal

Pre-submission checklist

• Code builds and passes locally
• PR title follows Conventional Commit format (e.g. test #001: created unit test for __ component)
• Request reviews from the Peer Code Reviewers and Senior+ Code Reviewers groups
• Thread has been created in Discord and PR is linked in gis-code-questions

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Preview	Comments	Updated (UTC)
elecretanta	Ready	Preview	Comment	Nov 13, 2025 10:52pm
elecretanta-storybook	Ready	Preview	Comment	Nov 13, 2025 10:52pm
elecretanta-unit-test	Ready	Preview	Comment	Nov 13, 2025 10:52pm