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)

tests/integration/InstallerCleanupTest.php

@@ -98,7 +98,7 @@ class InstallerCleanupTest extends TestCase {
 	/** tmdo_* options and transients were left behind; a reinstall then saw stale deferrals and indexes (F-5). */
 	public function test_uninstall_removes_tmdo_options_and_transients(): void {
 		global $wpdb;
-		foreach ( array( 'tmdo_schema_deferred', 'tmdo_entity_indexes', '_transient_tmdo_cov_x', '_transient_timeout_tmdo_cov_x', 'hivepress_settings' ) as $name ) {
+		foreach ( array( 'tmdo_schema_deferred', 'tmdo_entity_indexes', '_transient_tmdo_cov_x', '_transient_timeout_tmdo_cov_x', 'hivepress_settings', 'tmdo_latepoint_db_version' ) as $name ) {
 			$wpdb->insert( $wpdb->options, array( 'option_name' => $name, 'option_value' => '1' ) );
 			$GLOBALS['_wp_options'][ $name ] = '1';
 		}
@@ -109,6 +109,7 @@ class InstallerCleanupTest extends TestCase {
 			$this->assertArrayNotHasKey( $name, $GLOBALS['_wp_options'], $name );
 		}
 		$this->assertArrayHasKey( 'hivepress_settings', $GLOBALS['_wp_options'], 'other plugins untouched' );
+		$this->assertArrayHasKey( 'tmdo_latepoint_db_version', $GLOBALS['_wp_options'], 'the LatePoint add-on owns it' );
 	}
 
 	public function test_drops_static_tables(): void {