fix(cron): birthday notifications require 1+ year like adoptedAt

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/api/cron/anniversaries/route.ts

@@ -24,6 +24,7 @@ export async function GET(req: Request) {
     WHERE birthday IS NOT NULL
       AND EXTRACT(MONTH FROM birthday) = ${month}
       AND EXTRACT(DAY FROM birthday) = ${day}
+      AND birthday <= NOW() - INTERVAL '1 year'
   `;
 
   // Find all pets whose adoptedAt matches today and was at least 1 year ago