[FEATURE] Being able to switch accounts manually

[nxtkofi]

Feature Description
Manual account switching in opencode or outside

Use Case
well it would be nice to per-se at the start of session send a simple "hi" to each of the accounts to start the 5 hour window.
afaik the only way to switch now is to run out of tokens? which idk just feels weird.

Compliance Consideration
Please confirm:

• This feature is for personal development use
• This feature does not violate or circumvent OpenAI's Terms of Service
• This feature is not intended for commercial resale or multi-user access

Additional Context
idk it feels weird to only be able to switch by asking another model to do it. Even CLI arg would be genuinely useful.