Fix race condition in magic link token verification and typo in auth error message

- Hold SELECT FOR UPDATE lock within transaction by using tx directly instead of separate WithConn, ensuring mutual exclusion when multiple requests race to verify the same token
- Fix "resouce" → "resource" typo in authentication error messages

Signed-off-by: Bryan Frimin <bryan@getprobo.com>

pkg/server/api/authn/identity_presence_middleware.go

@@ -37,7 +37,7 @@ func NewIdentityPresenceMiddleware() func(next http.Handler) http.Handler {
 							Errors: gqlerror.List{
 								gqlutils.Unauthenticatedf(
 									r.Context(),
-									"authentication is required to access this resouce",
+									"authentication is required to access this resource",
 								),
 							},
 						},