refactor(remote): remove legacy single-remote storage in favor of remotes table

Drops the per-profile remote_storage column and all legacy FTP/SFTP/S3/
Google Drive credential columns. Remote destinations are now sourced
exclusively from #__mokosuitebackup_remotes (multi-remote), which is
created at install time — so the backward-compat fallback branches in
BackupEngine, SteppedBackupEngine and loadRemoteDestinations are removed.

- sql: drop 26 legacy columns (install.mysql.sql + 02.52.25.sql migration)
- forms/profile.xml: remove legacy remote fields and ftp/gdrive/s3 fieldsets
- tmpl/profile/edit.php: drop legacy UI, add save-first prompt, use
  getOrCreateInstance for the modal, read item.params (was item.config)
- PreflightCheck: validate credentials from the remotes table; curl
  warning now applies to ntfy only
- SteppedSession: drop remoteStorage property
- language: add backup-record delete-count strings
- script.php: simplify postflight license-key prompt

source/script.php

@@ -665,41 +665,23 @@ class Pkg_MokoSuiteBackupInstallerScript
 	{
 		try
 		{
-			$db = Factory::getDbo();
-			$db->setQuery(
-				$db->getQuery(true)
-					->select([$db->quoteName('update_site_id'), $db->quoteName('extra_query')])
-					->from($db->quoteName('#__update_sites'))
-					->where('(' . $db->quoteName('name') . ' LIKE ' . $db->quote('%MokoSuiteBackup%') . ' OR ' . $db->quoteName('location') . ' LIKE ' . $db->quote('%MokoSuiteBackup%') . ')')
-					->setLimit(1)
-			);
-			$site = $db->loadObject();
-
-			if ($site)
-			{
-				$eq = (string) ($site->extra_query ?? '');
-				if (!empty($eq) && strpos($eq, 'dlid=') !== false) { parse_str($eq, $p); if (!empty($p['dlid'])) { return; } }
-				$editUrl = 'index.php?option=com_installer&task=updatesite.edit&update_site_id=' . (int) $site->update_site_id;
-			}
-			else
-			{
-				$editUrl = 'index.php?option=com_installer&view=updatesites';
-			}
-
 			Factory::getApplication()->enqueueMessage(
-				'<strong>Moko Consulting License Key Required</strong> — '
-				. 'No download key is configured. Updates will not be available until a valid license key is entered. '
-				. '<a href="' . $editUrl . '" class="btn btn-sm btn-warning ms-2">Enter License Key</a>',
-				'warning'
+				'<h4>MokoSuiteBackup installed successfully!</h4>',
+				'info'
+			);
+			
+			// Show post-install license key prompt
+			Factory::getApplication()->enqueueMessage(
+				'<strong>Moko Consulting License Key Required</strong><br>'
+					. 'A download key (DLID) is required to receive updates. '
+					. 'Enter your key in the <a class="btn btn-sm btn-warning ms-2" href="index.php?option=com_installer&view=updatesites&filter[search]=moko">Update Sites</a> manager '
+					. 'or contact <a class="btn btn-sm btn-warning ms-2" href="https://mokoconsulting.tech/support">Moko Consulting Support</a> to obtain one.',
+					'warning'
 			);
 		}
-		catch (\Exception $e) {
-			error_log('MokoSuiteBackup: License key check failed: ' . $e->getMessage());
-			Factory::getApplication()->enqueueMessage(
-				'MokoSuiteBackup could not verify your license key status. '
-				. 'Please check System &rarr; Update Sites to ensure a valid license key is configured.',
-				'warning'
-			);
+		catch (\Exception $e)
+		{
+			error_log('MokoSuiteBackup: License key prompt failed: ' . $e->getMessage());
 		}
 	}
 }