chore(web): drop unused health route (#101)

Removes the web api/health route — approved in the hardening plan (rev
5.1 unblocked deletions; no in-repo consumers, no external monitors per
owner) — and updates the README verification note to the /health/live
worker endpoint. NEXT_PUBLIC_VERCEL_GIT_COMMIT_SHA remains live via
packages/env web config and next.config.

Author: iamjr15

apps/web/README.md

@@ -80,5 +80,5 @@ Production additionally admits only Vercel's exact immutable deployment origin.
 Vercel's Git integration deploys `apps/web` from the repository using the
 checked-in build command. Production public environment values select the live
 Clerk instance and canonical gateway; deployment identity selects the owned
-preview apex. Verify `/api/health` and the deployed revision after Vercel
-finishes.
+preview apex. Verify the deployed revision in the Vercel dashboard after the
+build finishes; worker liveness is `gateway.trycheatcode.com/health/live`.