When a contact or group has a simplex_name stored, the share-link
render path emits the canonical simplex:/name... URI (via strEncode)
instead of the underlying connection link. Falls back to the existing
link rendering when simplexName is Nothing.
Final commit of the ConnectTarget plumbing chain: end-to-end users
can now (a) connect via @alice.simplex / #group.simplex with the
agent layer carrying the name, (b) see the simplex name on the
contact/group records and in viewConnectionPlan, (c) share the
contact using the namespace-canonical form rather than the raw URI.