Adds the Send files action to the device detail, routing the picked
selection through sendToContact.
Rather than a second picker path, sharePickedFiles now takes a
ShareDestination, so the macOS security-scoped access handling covers both
routes. A contact destination carries no access policy, matching the core's
rule that an offer share is never public.
Device list, detail, and block list under Settings, plus the two sheets:
an incoming offer and a device asking to be remembered. Both are
answer-only, since swiping away would leave the sender waiting.
Accepting an offer routes the released ticket into the ordinary receive
path, so the platform still chooses the destination. The prompt does not
ask a second time; it only falls back to the review sheet when the
destination is unusable.
