feat: add user instructions to viewer popup

__tests__/run.mjs

@@ -3,6 +3,7 @@
  */
 import './schema.test.mjs';
 import './viewer_units.test.mjs';
+import './instructions_ui.test.mjs';
 import './data_flow.test.mjs';
 import './viewer_integration.test.mjs';
 import './config_validation.test.mjs';