chore(admin-cli): tidy mlx command output (sink, CSV, YAML, wording)

[chet]

While realigning the admin CLI onto the Dispatch + Run traits (#2951),
CodeRabbit surfaced four pre-existing rough edges in mlx command output. Each
is a behavior change, so they were deliberately kept out of that
no-behavior-change refactor -- this is the follow-up to tidy them up.

What this involves

• Honor the configured output sink. The mlx config commands
  (query/set/sync/compare) print via println!/printstd() and bypass
  ctx.output_file. Thread &mut ctx.output_file through and use the async
  write helpers so JSON/YAML/table output respects the selected destination.
  (Heads up: most of mlx prints directly today, so decide how far to take this
  -- it may be a broader pass than just config.) -- mlx/config/cmds.rs
• Error on unsupported CSV. mlx config query prints CSV not supported yet
  and exits 0 for --format csv; return a CarbideCliError so automation sees a
  non-zero exit. -- mlx/config/cmds.rs
• Safe YAML for profile list. The OutputFormat::Yaml arm hand-prints
  scalars (println!(" - profile_name: {}", ...)), which can misrender values
  needing escaping. Serialize through serde_yaml like the other YAML paths. --
  mlx/profile/cmds.rs
• Fix the machine-report error wording. InfoMachineCommand's handler says
  no device report found for device -- should read ...for machine. --
  mlx/info/cmds.rs

All four are pre-existing on main (not introduced by #2951); they were found
via CodeRabbit on PR #2953.