IAM Identity Center (authMethod=idc) tokens failed every request with 403
"bearer token invalid". Treat idc like api_key/external_idp:
- executors/kiro.js: route idc to *.amazonaws.com CodeWhisperer surface,
region-aware from credentials.region instead of hardcoded us-east-1.
- openai-to-kiro.js / claude-to-kiro.js: send resolved profileArn or empty
for idc/external_idp, never the shared builder-id placeholder ARN.
Co-authored-by: Cursor <cursoragent@cursor.com>
