Merge pull request 'feat(engine): surface upstream move-type counters and replay seek' (#173) from feat/upstream-stat-counters into master

solitaire_server/web/replay.js

@@ -315,10 +315,9 @@ btnPlay.addEventListener("click", () => {
     }, STEP_INTERVAL_MS);
 });
 
-/// Step the player back one move. Re-creates the ReplayPlayer and fast-
-/// forwards to (step_idx - 1) without rendering intermediate frames, then
-/// renders once so the CSS transition animates each card to its previous
-/// position.
+/// Step the player back one move via the wasm-side seek (rewinds to the
+/// recorded deal and fast-forwards internally), then renders once so the
+/// CSS transition animates each card to its previous position.
 function stepBack() {
     if (!player || player.step_idx() === 0) return;
     if (playInterval) {
@@ -326,12 +325,7 @@ function stepBack() {
         playInterval = null;
         btnPlay.textContent = "▶ Play";
     }
-    const target = player.step_idx() - 1;
-    player = new ReplayPlayer(replayJson);
-    for (let i = 0; i < target; i++) {
-        player.step();
-    }
-    render(player.state());
+    render(player.seek(player.step_idx() - 1));
     btnPrev.disabled = player.step_idx() === 0;
     btnRestart.disabled = player.step_idx() === 0;
     btnStep.disabled = false;