Return every customer channel's state and next blocker for a workspace (sms:read).

One row per channel (voice, sms, whatsapp, imessage, rcs, messenger, instagram, webchat, email) with availability (live, built_off, planned), state (ready, needs_setup, blocked, not_available), canSend, canReceive and nextStep (id, description, optional tool naming the connector tool that takes the step). Read-only and derived from the same reads the per-channel endpoints use: sms is ready only once the business text registration is approved, and whatsapp only on a verified number. Email includes a separate managedEmail object (state, canSend, reasons, tool) for campaign sender/trust/release readiness; a connected mailbox does not prove campaign readiness. Sender readiness never proves owner approval or delivery. Mirrors the get_channel_status tool.