M1: key management, backup locations and occ commands

- migration: ngb_targets, ngb_runs, ngb_snapshots
- KeyService: master key stored encrypted with the instance secret
  (unattended backups), passphrase-wrapped copy in every repository and
  in the recovery kit, recorded admin confirmation per key fingerprint
- TargetService: locations built from files_external backends without a
  mount; files_external is loaded through IAppManager::loadApp() and its
  enabled state is left alone; credentials encrypted with ICrypto;
  existing repositories are adopted only if made with this key, and a
  repository cannot be registered twice
- Repository: initWithKey/openWithKey with an encrypted key check
- occ: backup:key:init|kit|confirm, backup:target:backends|add|list|remove

lib/Command/TargetList.php

@@ -0,0 +1,57 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup\Command;
+
+use OC\Core\Command\Base;
+use OCA\NgBackup\Service\TargetService;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Input\InputOption;
+use Symfony\Component\Console\Output\OutputInterface;
+
+class TargetList extends Base {
+	public function __construct(
+		private TargetService $targets,
+	) {
+		parent::__construct();
+	}
+
+	protected function configure(): void {
+		parent::configure();
+		$this->setName('backup:target:list')
+			->setDescription('List backup locations')
+			->addOption('test', 't', InputOption::VALUE_NONE, 'Also connect to each location and check the repository');
+	}
+
+	protected function execute(InputInterface $input, OutputInterface $output): int {
+		$rows = [];
+		foreach ($this->targets->list() as $t) {
+			$row = ['id' => $t->getId(), 'name' => $t->getName(), 'backend' => $t->getBackend(), 'path' => $t->getBasePath(),
+				'repository' => $t->getRepositoryId(), 'added' => date('Y-m-d H:i', $t->getCreatedAt())];
+			if ($input->getOption('test')) {
+				try {
+					$repo = $this->targets->repository($t);
+					$row['status'] = 'ok, ' . count($repo->listSnapshots()) . ' snapshots';
+				} catch (\Throwable $e) {
+					$row['status'] = 'error: ' . $e->getMessage();
+				}
+			}
+			$rows[] = $row;
+		}
+		if ($input->getOption('output') === self::OUTPUT_FORMAT_PLAIN) {
+			if ($rows === []) {
+				$output->writeln('No backup locations yet (occ backup:target:add).');
+				return 0;
+			}
+			$table = new \Symfony\Component\Console\Helper\Table($output);
+			$table->setHeaders(array_keys($rows[0]))->setRows(array_map('array_values', $rows))->render();
+		} else {
+			$this->writeMixedInOutputFormat($input, $output, $rows);
+		}
+		return 0;
+	}
+}