Solution:
I think, the problem with jQuery wrong usage. Probably, wrapping the function with jQuery allows using $ variable and could solve the problem
jQuery(function($){
$( '#photo-button' ).on( 'click',
function () {
$( '#display-photo' ).html("Hello <b>world!</b>");
}
);
})
The second required thing is to set jQuery as a dependency for your script and to update the script version to 1.1.
wp_enqueue_script( 'main-js', get_template_directory_uri() . '/assets/src/library/js/main.js', array( 'jquery' ), '1.1', true );