feat: Refresh AWS SSO sessions without requiring AWS CLI #194

Summary

Improve profile selector SSO login so claws can refresh or start AWS SSO sessions directly via the AWS SDK, instead of relying on aws sso login.

Motivation

The current SSO login flow depends on the AWS CLI being installed and shells out to aws sso login. It would be better if claws could reuse existing SSO cache entries, refresh sessions when possible, and only start browser/device authorization when needed.

Expected behavior

Pressing l on an SSO profile should:

• reuse an existing valid SSO session when available
• refresh the standard AWS SSO cache when possible
• start the browser/device authorization flow when login is required
• support profiles using sso-session config blocks