Headless Channel Setup (type-agnostic)

Top-level orchestrator: given a messaging channel type and its inputs, produces an activated Enhanced `MessagingChannel` in the target org — without the Meta/LINE/Apple setup popups. Prompts for `{MESSAGE_TYPE}` if not supplied, then sequences insert → route → consent → activate via the type-agnostic dispatcher (`service-de-channel-create`) plus the shared routing/consent/activation leaves. Resumes from partial state on re-run. Use to set up an Enhanced channel (WhatsApp, Facebook, LINE, Apple, SMS) end-to-end, bypassing in-org setup popups. Do not use for a single stage of an already-inserted channel — use the matching leaf skill (`service-de-channel-activate`, `service-…