Invalid --url / NSC_URL crashes with an internal error #186

resolve_profile builds HttpUrl(url) without catching the pydantic ValidationError, so a malformed URL escapes as an internal error with a traceback instead of a usage/config error.

Repro

NSC_TOKEN=x nsc --url not-a-url dcim sites list

→ {"error":"internal error: 1 validation error for function-wrap[wrap_val()] Input should be a valid URL…", a traceback, exit 1.

Expected: exit 2, invalid NetBox URL 'not-a-url' (from --url), the same shape as the #179 fix. NSC_SCHEMA/--schema URLs probably need the same treatment.

Found in the adversarial review of #185.