Fix provider identification when both email providers fail (#59)

* Initial plan

* Fix dual-provider failure to return secondary provider name

Co-authored-by: devakesu <61821107+devakesu@users.noreply.github.com>

* Add non-null assertion for secondaryName

Co-authored-by: devakesu <61821107+devakesu@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: devakesu <61821107+devakesu@users.noreply.github.com>

Author: Copilot

src/lib/email.ts

@@ -135,13 +135,15 @@ export async function sendEmail(props: SendEmailProps) {
   let primary: typeof sendViaSendPulse | typeof sendViaBrevo;
   let secondary: typeof sendViaSendPulse | typeof sendViaBrevo | null = null;
   let primaryName: string;
+  let secondaryName: string | null = null;
 
   // If both available, randomize
   if (hasBrevo && hasSendPulse) {
     const startWithSendPulse = Math.random() < 0.5;
     primary = startWithSendPulse ? sendViaSendPulse : sendViaBrevo;
     secondary = startWithSendPulse ? sendViaBrevo : sendViaSendPulse;
     primaryName = startWithSendPulse ? "SendPulse" : "Brevo";
+    secondaryName = startWithSendPulse ? "Brevo" : "SendPulse";
   } 
   // If only one available, use it
   else if (hasSendPulse) {
@@ -170,7 +172,7 @@ export async function sendEmail(props: SendEmailProps) {
         console.error("All email providers failed.");
         return {
           success: false,
-          provider: "Brevo" as const,
+          provider: secondaryName! as "Brevo" | "SendPulse",
           error: `Primary: ${primaryError.message} | Secondary: ${secondaryError.message}`,
         };
       }