feat: Brevo SMTP email config, fire-and-forget verification emails

- Configure Brevo SMTP (smtp-relay.brevo.com:587) for production emails
- Make sendVerificationEmail fire-and-forget so SMTP failures don't block registration
- Update .env with real SMTP credentials and APP_URL=https://gammanexus.io
- Fix resend-verification to also use non-blocking email send

server/authRoutes.ts

@@ -59,8 +59,10 @@ export function registerAuthRoutes(app: Express) {
       const expiry = new Date(Date.now() + 24 * 60 * 60 * 1000); // 24 hours
       await updateUserVerification(user.id, token, expiry);
 
-      // Send verification email
-      await sendVerificationEmail(sanitizedEmail, sanitizedName, token);
+      // Send verification email (fire-and-forget — don't block registration on SMTP failure)
+      sendVerificationEmail(sanitizedEmail, sanitizedName, token).catch((err) => {
+        console.error("[Auth] Verification email failed (non-blocking):", err);
+      });
 
       res.status(201).json({ 
         ok: true, 
@@ -163,7 +165,10 @@ export function registerAuthRoutes(app: Express) {
       const token = crypto.randomUUID();
       const expiry = new Date(Date.now() + 24 * 60 * 60 * 1000);
       await updateUserVerification(user.id, token, expiry);
-      await sendVerificationEmail(user.email, user.name, token);
+      // Fire-and-forget — don't block response on SMTP failure
+      sendVerificationEmail(user.email, user.name, token).catch((err) => {
+        console.error("[Auth] Resend verification email failed (non-blocking):", err);
+      });
 
       res.json({ ok: true, message: "Verification email sent. Please check your inbox." });
     } catch (error) {