signal-ui/src/main.jsx hardcoded WEBAPP_URL to https://signal-ui-xi.vercel.app
and passed it to signInUrl/signUpUrl/afterSignInUrl/afterSignUpUrl. The
production Clerk instance (clerk.sttilsolutions.com) rejects that origin with
400 origin_invalid on every write path, so sign-in was handed back to an origin
that cannot authenticate. Verified live: POST /v1/client/sign_ins returns 400
from the Vercel origin and 200/422 from signal.sttilsolutions.com.
Redirect target now derives from window.location.origin, overridable via
VITE_APP_URL, so it cannot drift from the deployed domain again. Also replaced
afterSignInUrl/afterSignUpUrl with signInFallbackRedirectUrl/
signUpFallbackRedirectUrl, deprecated in Clerk Core 2.
Build verified: pnpm build succeeds, dead Vercel URL absent from dist output.
NOT verified: a real sign-in completing end to end. Needs deploy first.
Also updates the pilot readiness table: hosted-URL row now names
signal.sttilsolutions.com (confirmed canonical by Kisa 2026-07-27), login row
moved from PASS to OPEN. Honest count 11/13 clean, 1 open, 1 disputed.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Aqzsyo1PudjabuV9XQzxwp
65d0e13008