v0.8.0.5 — the Home Office deck, and lighting the pile a move touched

"Many operations still occurred too fast for me to see", at 10x — where an action
already holds the screen for seven seconds. So it was never duration: a bot drawing
a card changes one number in a panel nobody is watching, and the board sits
unchanged. Raising the dwell was the wrong lever and it had been pulled three
times.

f.deck has carried the face-down count since the Frame existed and nothing drew it
— the display gap test/display-gaps.test.ts sweeps for, surviving in the one panel
that draws every other pile. It is a tile now, first in the row, face down, because
that is the order a card travels and not knowing what is on top is the point.

And the piles a move touched are lit for as long as that move is on screen. Derived
from the frames either side of a step rather than sent, so nothing joins the
protocol and the 0.8.1 board gets it free. What lights follows what is public, and
was measured across four seeds rather than reasoned about: a Home Office draw
lights the deck and never names the card; a Department draw lights that pile, and
the deck too when it refills; a discard lights the Department it lands on; a played
card lights the Salvage Yard. Switching and new trains light nothing here — they
move the board, which the district panel already follows.

A state rather than a flash: the timetable's fixed 1.5s animation would be over
long before a seven-second pause. Not for your own moves.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01X6cF1iYvJ1kNmzYBzu4QX6

src/web/step-queue.ts

@@ -19,7 +19,8 @@
 
 import type { PublicFrame } from '../sim/view.ts';
 import type { DisplayStep } from '../sim/display-step.ts';
-import { applyPublicDelta } from '../sim/public-delta.ts';
+import { applyPublicDelta, changedPiles } from '../sim/public-delta.ts';
+import type { PileKey } from '../sim/public-delta.ts';
 import { dwellForStep } from '../sim/pacing.ts';
 
 export type StepQueue = {
@@ -43,6 +44,13 @@ export type StepQueue = {
   behind(): number;
   /** The last step actually shown, for the caption line (#15). Null before anything has been shown. */
   showing(): DisplayStep | null;
+  /**
+   * The piles the step now on screen moved, for the display to light.
+   *
+   * Here because this is the only place that holds both the frame before a step and the frame after
+   * it — deriving it anywhere else would mean keeping a second copy of the board in step.
+   */
+  lit(): readonly PileKey[];
   /** True while there is anything left to show. */
   busy(): boolean;
 };
@@ -65,6 +73,7 @@ export function createStepQueue(
 ): StepQueue {
   let shown: PublicFrame | null = null;
   let last: DisplayStep | null = null;
+  let litPiles: readonly PileKey[] = [];
   let pending: DisplayStep[] = [];
   /** When the step now on screen is due to give way. Null when nothing is waiting. */
   let dueAt: number | null = null;
@@ -75,8 +84,14 @@ export function createStepQueue(
 
   /** Applies one step to the displayed board. A step's delta chains off the previous step's frame. */
   const show = (step: DisplayStep): void => {
+    const before = shown;
     shown = applyPublicDelta(shown, step.frame);
     last = step;
+    /**
+     * NOT FOR YOUR OWN MOVES. You drew that card; you do not need the deck flashed at you. Same rule
+     * that gives your own steps no dwell — the display is for watching everybody else.
+     */
+    litPiles = step.player !== null && step.player === viewer() ? [] : changedPiles(before, shown);
   };
 
   return {
@@ -84,6 +99,8 @@ export function createStepQueue(
       shown = frame;
       pending = [];
       dueAt = null;
+      // Nothing was watched arriving at this board, so nothing on it is lit.
+      litPiles = [];
       // `last` deliberately survives: a reconnect should not blank the caption line, and the
       // sentence describing the most recent action is still true.
     },
@@ -136,6 +153,7 @@ export function createStepQueue(
     current: () => shown,
     behind: () => pending.filter((s) => dwell(s) > 0).length,
     showing: () => last,
+    lit: () => litPiles,
     /**
      * STILL SHOWING SOMETHING, not just still holding something back.
      *