fix(2meet-data-optimizer): 1.4.2 acceptance fixes for archive sweep and uninstall

- Archive sweep waits until idx_original_meta exists (a plugin update does
  not run dbDelta; without the index NOT EXISTS scans the archive per row)
- Duplicate archive cleanup runs from WP-CLI only, never in a web activation
- Uninstall keeps the LatePoint add-on's tmdo_latepoint_db_version
- AJAX save errors stay on screen instead of fading after 2.5 s
- Verify: 2 new integration tests; unit 711, integration 612, phpcs 0, stan OK
- PR: PR-141 (2.4.2 correctness review)

admin/assets/wpdo-settings.js

@@ -45,7 +45,7 @@
 	}
 
 	/**
-	 * Show a transient status message, then fade it out after 2.5s.
+	 * Show a status message; success fades out after 2.5s, errors stay.
 	 *
 	 * @param {HTMLElement} statusEl
 	 * @param {string}      message
@@ -56,6 +56,9 @@
 		statusEl.style.color = isError ? 'var(--color-error, #b03d3d)' : 'var(--color-success, #5a8c5a)';
 		statusEl.classList.add( 'visible' );
 		clearTimeout( statusEl._wpdo_timer );
+		if ( isError ) {
+			return;
+		}
 		statusEl._wpdo_timer = setTimeout( () => {
 			statusEl.classList.remove( 'visible' );
 		}, 2500 );