I just finished the API integration for the billing module. Ready for review.

Nice, I'll pull it down now. Which branch?

feature/billing-api — it's based off the latest main. All tests passing locally.

Found one issue: the webhook signature verification is using the test key instead of the env variable.

Oh good catch — I hardcoded it while debugging and forgot to revert. Fixing now.

Looks clean now. Approved the PR. Let's ship it after the smoke test.

Smoke test passed. Merging to main and deploying to staging.