Fix for webhook authorization failures caused by Base64 padding character (=) being
dropped when copying secrets between systems. Use when: (1) Webhook returns "Unauthorized"
or "Server Error" but the secret looks correct, (2) INTERNAL_API_SECRET, WEBHOOK_SECRET,
or similar auth tokens fail validation between Railway/Vercel and Convex/database,
(3) Secret comparison fails despite values appearing identical, (4) CLI tools display
truncated environment variables. Common with Railway CLI, Vercel CLI, and other
deployment platforms that may not display trailing = characters.