chat.openDM dispatches via inferAdapterFromUserId, which only recognizes
Discord/Slack/Teams/gChat formats and throws for everything else —
breaking approval delivery on Telegram (numeric IDs) and the other
direct-addressable channels the bridge now wraps. Delegate straight to
adapter.openDM + channelIdFromThreadId, and only expose openDM when the
underlying adapter implements it. Preserves the adapter's native
platform_id encoding (e.g. "telegram:<chatId>") so user_dms caches align
with the messaging_groups rows onInbound wrote.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>