feat(timeline): let a lane be one deadline queue, started or not

`endingSoonestFirst` holds every unstarted event behind every running
one. That is right for a checklist — you cannot do a thing that has not
opened — and it is one answer of two for a board, which is asked what
runs out first. An event opening on Friday and closing on Sunday is a
nearer deadline than one running now until October, and that order can
never show it.

So `byDeadline` is the same comparator with that clause removed, and
`timelineLanes` takes a `split` flag choosing between them. It defaults
to the old behaviour, so nothing moves yet.

The flag is also the one case where lane mode reorders inside a lane,
which the module otherwise refuses to do. Deliberate: the given order is
live-first whatever the reader chose in the list, so honouring it would
draw exactly the block this was asked not to draw.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

src/client/state/lanes.ts

@@ -1,5 +1,5 @@
 import type { LaneId } from "../../shared/custom.ts";
-import { endingSoonestFirst, type EventClock } from "../../shared/time.ts";
+import { byDeadline, endingSoonestFirst, type EventClock } from "../../shared/time.ts";
 
 /**
  * How the timeline is stacked: a lane per game, or every game together in
@@ -65,19 +65,35 @@ export interface Lane<T> {
  * Lane mode leaves the order it was given alone. The rows arrive sorted by
  * whatever the reader chose in the list, and grouping them by game is not a
  * licence to re-sort inside a game.
+ *
+ * `split` is the exception to that last sentence, and deliberately so. Both
+ * orders above hold every unstarted event behind every running one, which is
+ * the segregation the board's "Not started yet" heading names — so a reader who
+ * asks for them mixed in is asking for exactly that clause to be dropped, and
+ * `byDeadline` is the same comparator with it gone. It applies in **both**
+ * modes, lane mode included: leaving a lane's given order alone there would
+ * produce the block it was told not to draw, minus the heading that explained
+ * it, which is the worst of both answers.
  */
 export function timelineLanes<T extends Row>(
   rows: readonly T[],
   mode: TimelineGroup,
+  split = true,
 ): Array<Lane<T>> {
+  const order = split ? endingSoonestFirst : byDeadline;
+
   if (mode === "ending") {
     if (rows.length === 0) return [];
-    return [{ id: "all", game: null, rows: [...rows].sort(endingSoonestFirst) }];
+    return [{ id: "all", game: null, rows: [...rows].sort(order) }];
   }
 
   const byGame = new Map<LaneId, T[]>();
   for (const row of rows) {
     byGame.set(row.event.game, [...(byGame.get(row.event.game) ?? []), row]);
   }
-  return [...byGame].map(([game, laneRows]) => ({ id: game, game, rows: laneRows }));
+  return [...byGame].map(([game, laneRows]) => ({
+    id: game,
+    game,
+    rows: split ? laneRows : [...laneRows].sort(byDeadline),
+  }));
 }

src/shared/time.ts

@@ -344,6 +344,30 @@ export function endingSoonestFirst(
   return a.clock.msRemaining - b.clock.msRemaining;
 }
 
+/**
+ * Sort key: soonest deadline first, and nothing else.
+ *
+ * The other half of the timeline's "put them all together" (PRD F1). Where
+ * `endingSoonestFirst` holds every unstarted event behind every running one —
+ * which is what a *checklist* wants, since you cannot do a thing that has not
+ * opened — this asks the one question a Gantt board is for: what runs out
+ * first. An event opening on Friday and closing on Sunday is a nearer deadline
+ * than one running now until October, and a reader looking at a calendar rather
+ * than a to-do list is entitled to see it in that order.
+ *
+ * The `endsAt: null` rule is the same in both: an unannounced end is real but is
+ * not a deadline, so it sorts behind every dated row rather than claiming a
+ * place in the queue.
+ */
+export function byDeadline(
+  a: { clock: EventClock },
+  b: { clock: EventClock },
+): number {
+  if (a.clock.msRemaining === null) return b.clock.msRemaining === null ? 0 : 1;
+  if (b.clock.msRemaining === null) return -1;
+  return a.clock.msRemaining - b.clock.msRemaining;
+}
+
 /**
  * A plain-language caption for an event's window.
  *