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/ZoneArchiveIntegrationTest.php

@@ -29,7 +29,8 @@ class ZoneArchiveIntegrationTest extends TestCase {
 				`original_meta_id` bigint(20) unsigned NOT NULL DEFAULT 0,
 				PRIMARY KEY (`id`),
 				KEY `post_id` (`post_id`),
-				KEY `archived_at` (`archived_at`)
+				KEY `archived_at` (`archived_at`),
+				KEY `idx_original_meta` (`original_meta_id`)
 			) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4'
 		);
 	}
@@ -81,6 +82,20 @@ class ZoneArchiveIntegrationTest extends TestCase {
 		}
 	}
 
+	/** Until `wp tmdo install` adds the index, NOT EXISTS would scan the archive per candidate. */
+	public function test_sweep_waits_for_the_original_meta_index(): void {
+		global $wpdb;
+		$this->seed_trashed_post();
+		$wpdb->query( 'ALTER TABLE `' . self::TABLE . '` DROP INDEX `idx_original_meta`' );
+		try {
+			$this->assertSame( 0, WPDO_Zone_Archive::sweep( 90, false ) );
+			$this->assertSame( 0, $this->archive_rows() );
+		} finally {
+			$wpdb->query( 'ALTER TABLE `' . self::TABLE . '` ADD KEY `idx_original_meta` (`original_meta_id`)' );
+			$this->drop_posts();
+		}
+	}
+
 	public function test_remove_duplicates_keeps_the_first_copy_of_each_meta_row(): void {
 		WPDO_Zone_Archive::archive( 10, 'hp_listing', 'hp_price', '5', 101 );
 		WPDO_Zone_Archive::archive( 10, 'hp_listing', 'hp_price', '5', 101 );