一般的な開発タスク

Help me outline the overall architecture and main modules of this project.
Where is this feature implemented? Which files are involved?
Starting from the entry point, explain clearly how a single request is processed.
Where is this function called from?

Why did this test fail? Help me fix it
Run npm test, find the cause of the error and fix it
This API occasionally throws errors under concurrency, help me investigate

Extract the date processing functions in utils into a standalone module and update all references
Unify error handling across this directory while maintaining the same external behavior
Refactor these callbacks to use async/await, taking care not to alter the logic

Implement an Express middleware for request rate limiting
Complete the corresponding client methods based on this API documentation
Add form validation and error messages to this page

Add unit tests to this module, covering main branches
Write a regression test for the recent changes
Run tests and fix failing cases

Generate a commit message for these changes
Split related changes into semantically clear commits
Summarize the changes in this branch relative to main and write a PR description

Review my current changes and identify potential issues
Compare with the main branch and review this feature branch