PrivateV1 was the legacy prekey-handshake 1:1 protocol, superseded by
DirectV1 over InboxV2. Remove it and everything that existed only to
serve it.
- Delete PrivateV1Convo and its v1 inbox bootstrap: the Inbox,
Introduction, and InboxHandshake types, plus the support code only they
used (the crate::crypto module, EncryptionError, timestamp_millis, the
PrivateV1Domain HKDF domain, and the ServiceContext test doubles).
- Drop the public entry points that exposed it: Core::create_intro_bundle,
create_private_convo_v1, dispatch_to_inbox, and the matching
ChatClient::create_intro_bundle / create_conversation.
- Remove ConversationKind::PrivateV1 and its "private_v1" mapping, the
from_kind arm, and the orphaned inbox-v1 proto re-exports.
- Migrate the chat-cli /intro and /connect commands and the
message-exchange example to create_direct_conversation.
- Delete the PrivateV1 integration test; move the sqlite conversation
roundtrip test to GroupV1.
InboxOutcome, PayloadOutcome::Inbox, and ConversationClass::Private stay:
InboxV2 (DirectV1 and GroupV1 invites) still produces them.
Follow-ups, out of scope here:
- logos-chat-module still calls create_intro_bundle / create_conversation
and needs a companion change.
- remote_convo_id and EphemeralKeyStore are now vestigial (only PrivateV1
used them); dropping them is a storage-schema change for a later PR.
