DL-293

Creating a topic requires create_topic: true on the post, in every channel including DMs (PostMessageRequest.create_topic = 6; TopicRef.Create gates the store name path) — amends DL-098’s topic get-or-create clause (the Zulip threading model stays live; only auto-mint-on-miss is gated). A gated miss errors in-band not_found, never mints and never drops the message. Escape hatch (Matt): may revert for DMs only if it proves a blocker.

Status: Active (Matt, 2026-08-30)

Record: ../../agent/compass-agent-peer-dm/design.md#ledger-delta