Replace the bespoke in-CRM inbox with the SDK's <Inbox>, driven by a new
CrmInboxAdapter over the be-crm data door (crm.inbox.* + crm.mail.*).
Demo mode falls back to the SDK MockInboxAdapter. Maps --miu-* tokens for
.miu-inbox to the CRM theme.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
