[AlphaJack]

Fixes #1951

--long no longer conflicts with --json. With both, each entry is an object with its path, the node's type and its metadata, using the same field names as the nodes of cat tree:

[
{"path":"data/dir","type":"dir","mode":2147484141,"mtime":"2026-10-15T22:48:28.543472128+02:00","atime":"…","ctime":"…","uid":1000,"gid":1000,"user":"jack","group":"jack","inode":11408871},
{"path":"data/dir/file.txt","type":"file","mode":420,"mtime":"2026-10-15T22:48:28.543472128+02:00","atime":"…","ctime":"…","uid":1000,"gid":1000,"user":"jack","group":"jack","inode":11408872,"size":6,"links":1}
]

• --json alone is unchanged (an array of paths), so existing users aren't affected.
• Times are RFC 3339 with their offset.
• name (it's in path), content (the data blob ids, one per chunk, large for big files) and subtree are left out.
• mode is the raw value as stored, like in cat tree; for directories it includes the directory bit.
• Directories that rustic creates above the backup path have no metadata, so they only have type and mode.

Tests

test_ls_json_long_has_metadata (in tests/backup_restore.rs) backs up, runs ls --json --long latest and checks that every entry has a path and a type, and every file an mtime and a size.