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The Clerk publishable key was not baked into this build.
Set CLERK_PUBLISHABLE_KEY (or NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY) on the Railway service and redeploy,
or replace pk_test_cmVsYXRpdmUtY2F0ZmlzaC0xMS5jbGVyay5hY2NvdW50cy5kZXYk in index.html for local dev.