Declared-origin taxonomy for the Adicionar Lead selector

Options for the manual "Origem da lead" selector (ticket #726).

Served from the backend so the frontend cannot drift from the keys actually persisted in Z_Leads.declared_origin — the mistake SOURCE_OPTIONS / REQUEST_SOURCE_LABELS already made in call-tracking, where two hand-synced copies of the same list live in two repos.

The list is GLOBAL, not tenant-scoped: a declared "standvirtual" has to be the same key for every company or it stops being comparable to the measured one. Hence no idcompany here — there is no tenant data to leak. Auth still applies (protected_router is gated globally).