v0.5.0: The token counts four agents were already writing

• Token counts for Claude Code, Codex, Pi and CommandCode, which all record
  what a turn spent and were simply never read. Seven of the eight agents now
  report what a session cost.
• The counts are summed over a whole log, which is the one thing here that
  reads a file end to end, so it happens only for the session whose detail
  panel is open. Logs are append only, so a session that grew costs the bytes
  it just wrote rather than all of it again.
• agent-ps list now says when ps or lsof failed even where the table came
  back with rows, rather than only when it came back empty.
• The tests run in CI, across every supported interpreter.