-a, --agent <name> to choose an agent per invocation

[Suree33]

I usually ask Codex, but depending on the question I sometimes want to ask Claude Code instead.

Right now that means running ‎ask --settings to switch the default agent, then switching it back afterwards. It would be convenient to specify the agent just for a single invocation:

$ ask -a claude why is this container restarting?

Proposal

• Add -a, --agent <name>, accepting the same agent names as ask --settings (aliases included).
• The override applies to that invocation only. The configured default stays untouched.
• Model/reasoning follow the configured settings for the chosen agent.
• A session started this way remembers its agent, so ask -c continues with it.
• Combining with -c / -s is a usage error: a session is bound to the agent it started with.