Keep leases alive during long restores and exports; PR review fixes

Full restore, raw directory restore, per-user export and the safety export
held a fixed-TTL lease on the location that nothing refreshed. A restore or
export running longer than that TTL let a cleanup take over and delete data
still in use. They now refresh the lease while they work (per blob, per row
batch, per written chunk), throttled to once a minute.

Also:
- backup:prune still applies snapshot retention when user-export retention
  fails for a location.
- The recovery kit carries the deletion delay, so a disaster recovery keeps
  the original protection instead of falling back to 7 days. Older kits
  still import with the default.
- CI checkouts no longer persist the token in the git config.
- recoveryKit() has its real return type; the stale baseline entry is gone.

lib/Db/DbDumper.php

@@ -132,7 +132,7 @@ final class DbDumper {
 	 *
 	 * @param array{tables: array<string, array{blobs: list<string>, rows: int}>} $manifest
 	 */
-	public function restore(Repository $repo, array $manifest, ?array &$report = null): int {
+	public function restore(Repository $repo, array $manifest, ?array &$report = null, ?callable $heartbeat = null): int {
 		$sm = $this->db->createSchemaManager();
 		$existing = array_flip($sm->listTableNames());
 		$total = 0;
@@ -175,6 +175,9 @@ final class DbDumper {
 					if (count($batch) >= self::INSERT_ROWS) {
 						$total += $this->insertBatch($table, $columns, $batch, $binary);
 						$batch = [];
+						if ($heartbeat !== null) {
+							$heartbeat();
+						}
 					}
 				}
 				if ($batch !== []) {