Diskless sessions no longer write command output to files

What

Some sessions are launched with a diskless option (host.launchOptions.diskless()), meaning the session writes no files. Task output is the text produced by commands and background tasks. Its handling now respects this option in two places:

• The TaskOutput buffer assigns no output file path in a diskless session. When output passes the in-memory limit, later output is dropped instead of being written to a spill file on disk, and the reader gets the notice "later output was discarded because this session writes no files." Before, a spill file was always created once the limit was exceeded.
• The check that sets outputFileReadable for background task output (CP(tools)) now returns false first when the session is diskless. Before, it looked only at which tools were available. As a result, Claude is not told to read task output files in these sessions.

Why

Diskless sessions no longer try to write output files they are not allowed to create. The cost is that very long output from a command is cut off in these sessions, so expect truncation if you rely on the full output of a long-running command.