* fix: infer --auth-choice from API key flags during non-interactive onboarding
When --anthropic-api-key (or other provider key flags) is passed without
an explicit --auth-choice, the auth choice defaults to "skip", silently
discarding the API key. This means the gateway starts without credentials
and fails on every inbound message with "No API key found for provider".
Add inferAuthChoiceFromFlags() to derive the correct auth choice from
whichever provider API key flag was supplied, so credentials are persisted
to auth-profiles.json as expected.
Fixes#8481
* fix: infer auth choice from API key flags (#8484) (thanks @f-trycua)
* refactor: centralize auth choice inference flags (#8484) (thanks @f-trycua)
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Co-authored-by: f-trycua <f@trycua.com>
22927b0834