[Feature] Add an option to display Immich-specific storage usage

I have searched the existing feature requests, both open and closed, to make sure this is not a duplicate request. • Yes The feature I'm running Immich on a NAS where the storage volume is shared with other services, including a torrent client and a file storage service. Currently, the storage widget shows 1.2 TiB of 21.8 TiB, even though Immich itself only stores approximately 200 GiB of photos and videos. The remaining used space belongs to other applications. I'd like an option to display Immich's actual storage usage instead of the total filesystem usage. For example, instead of: 1.2 TiB / 21.8 TiB It could show: 200 GiB / 20.8 TiB The idea is to calculate the available capacity as: Immich storage usage + remaining free space on the filesystem This way, storage occupied by unrelated applications wouldn't be counted as Immich usage, while the available space would still reflect the actual free capacity of the shared volume. …