My Next.js app signs users in flawlessly while running in development mode, yet every authentication attempt fails with an “Authentication failure” once the production build is deployed. I need someone who can dive straight into the JWT flow, pinpoint why the token validation breaks only in prod, and deliver a concise fix I can merge and redeploy quickly. Scope (keep it lean and focused): • Audit the current login / refresh logic and environment-specific configs. • Replicate the production issue, identify root cause, and patch the code or build settings. • Provide clear, step-by-step notes so I understand what changed and why. I’d like to start ASAP, so please send a brief but detailed project proposal that explains how you’ll approach the problem, any relevant tools or libraries you’ll use (e.g., next-auth, jsonwebtoken, cookies), and an estimated timeline.