When model_profile is set to "inherit" in config.json, resolveModelInternal()
now returns "inherit" immediately instead of looking it up in MODEL_PROFILES
(where it has no entry) and silently falling back to balanced.
Also adds "inherit" to the valid profile list in verify.cjs so setting it
doesn't trigger a false validation error.
Closes#1829
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
