Resolve merge conflicts

The feature branch and main both have conflicting changes to the API client. Resolve the merge conflicts, run the unit tests, and push the merged branch so CI can rerun. Start by confirming no behavior regression in the client and that the public method signatures are unchanged before pushing.

Before I merge this branch into main, make the conflict resolution obvious to a reviewer: show a short summary at the top describing which file sections I changed and why, highlight any behavioral changes to the API client, and list the handful of tests I ran locally with their results.

I pulled the feature branch and main; there are merge markers in src/client.js, src/auth.js, and README.md. I am unsure whether to keep the client method renaming in client.js or the older name in main because both have downstream callers. I can run the test suite but the integration tests take 20 minutes. What is the likely safe choice and the best next step to be confident before pushing?

We keep losing time resolving the same API surface conflicts between feature branches and main, often with different people renaming methods or changing call signatures. Where should we change our habits: branch strategy, review checklist, or API ownership, so this happens less and reviewers trust merges? Recommend the single most impactful habit to adopt and one practical rule to enforce in PRs.