Vercel Hobby function cap breaks when parallel branches merge

On Vercel Hobby, a project with no framework counts each file in api/ as one function, and the cap is 12 per deployment. Every feature branch can pass on its own (9 base + 3, or 9 + 2) and then fail at production deploy once two branches land together. Count api/ files on every open branch, not only the one you are planning. Put the related endpoints into one dispatcher file that routes by sub-path through one vercel.json rewrite. Add a test that fails when api/ holds more than 12 function files, so the merge that goes over the cap fails in CI and not at deploy.