The resolver only enumerated guild channels, so any v1 install whose
registered Discord chat was a DM (a common case for personal-bot
installs) failed 1b-db with "not found in any guild" — leaving the
migration without an agent_group or wiring, and the user with a bot that
received messages but had nowhere to route them.
Add an unresolved-channel classification pass: for any v1 channel id not
found in a guild, GET /channels/<id> and emit discord:@me:<id> when the
type is DM (1) or GROUP_DM (3). Matches the runtime adapter's
guild_id || "@me" encoding. Other types / 404 / 403 keep current
skip-with-warning behavior.
Caller passes the v1 channel id list (already on hand). Test coverage
extends the existing mock-fetch pattern with DM, GROUP_DM, orphan, and
dedupe cases.
8181054bdb