feat(assistant): change cards in the style of the planner's day list

A waiting change is one row as in the day list: a round choice in front,
what it touches in bold, a faint line with what happens and when. No switch,
nothing to fold open, no day band: the planner's day list already shows the
suggestion among the day's stops. Whether the days still fit is one pill in
the card's head, with what to look at on hover.

Also mends the comment the rebase onto dev split in json-columns.ts.

server/src/db/json-columns.ts

@@ -332,6 +332,8 @@ export const JOURNEY_RECORDED_DAY_SEGMENTS: JsonColumn<DawarichTrackSegment[]> =
   schema: z.array(dawarichTrackSegmentSchema),
   fallback: () => [],
 };
+
+/**
  * The parts of an assistant message as the client renders them: text, tool
  * calls with their results and approvals, change previews and receipts. A
  * broken row reads as an empty message and is logged.