Add agent provider command to set per-agent provider and model (#76)
Adds a new tinyclaw agent provider <id> [provider] [--model MODEL]
subcommand that allows setting an individual agent's AI provider and
model without going through the interactive agent add flow.
https://claude.ai/code/session_01FkQ7d2jzWfi2zVj3yadDmZ
Co-authored-by: Claude noreply@anthropic.com