Rows written before the gateway fix still carry the `[Triggering message
id: …]` note as the first line of `content`. `displayContentForMessage`
already projects user rows for display (skill invocations, attached
context); strip that one gateway envelope there as well — presentation
only, and only the note: the `[Replying to: "…"]` pointer next to it is
kept, and assistant rows are untouched.
Part of #114719
dcafb1900a