Limit the maximum amount of disk space that Lassie temp files can use

We are running Lassie in [Filecoin Station](https://www.filstation.app) - an app that runs on desktop computers of (possibly non-technical) users. We want Stations to be unobtrusive to the user and leave plenty of resources (e.g. free disk space) for user workloads.

To achieve that, we would like to limit how much space Lassie can use for temporary files.

A new configuration option for Lassie (the library) or Lassie Daemon (the HTTP server) would be ideal.

How easy or difficult would the implementation be? Are there any other options that would allow us to limit the maximum amount of disk space used? For example, I can imagine plugging in our custom block store if the Lassie library/daemon support that.

/cc @juliangruber

Start by reviewing the Lassie library and Lassie Daemon HTTP server configuration and temporary-file or block-store integration points. Determine whether a configurable maximum disk-usage limit can be applied in either entry point, and confirm completion by verifying that temporary files cannot exceed the configured limit.

Written by the indexing model from the issue text.