chore: add isMigrationApplied check for migration 0008

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

src/server/db/migrate.ts

@@ -240,6 +240,9 @@ async function isMigrationApplied(client: Pool, tag: string): Promise<boolean> {
   if (tag === "0007_invoice_email_message") {
     return columnExists(client, "public", "beenvoice_invoice", "emailMessage");
   }
+  if (tag === "0008_payments_recurring_public_links") {
+    return columnExists(client, "public", "beenvoice_invoice", "publicToken");
+  }
   // Unknown migration — assume not applied so it runs
   return false;
 }