feat: drive signs from a shared animation clock

src/scene/create-scene-controller.ts

@@ -573,6 +573,7 @@ function copyJourneySnapshot(snapshot: JourneySnapshot): JourneySnapshot {
       targetId: snapshot.sign.targetId,
       phase: snapshot.sign.phase,
       progress: finite(snapshot.sign.progress),
+      opacity: finite(snapshot.sign.opacity),
     } : null,
     arrived: Boolean(snapshot.arrived),
   };

src/scene/world/sign.ts

@@ -68,11 +68,18 @@ export function createSign(resources: SceneResourceBag) {
   return {
     group,
     update(sign: SignSnapshot | null) {
-      group.visible = sign !== null;
+      group.visible = sign !== null && sign.opacity > 0;
       if (!sign) return;
       updateTexture(sign.targetId);
-      const phaseOffset = sign.phase === 'approach' ? -26 : sign.phase === 'stabilized' ? -5 : 8;
-      group.position.set(7.2, 4.1, phaseOffset + sign.progress * 8);
+      material.opacity = sign.opacity;
+      const phaseOffset = sign.phase === 'anticipate'
+        ? -30
+        : sign.phase === 'approach'
+          ? -26 + sign.progress * 21
+          : sign.phase === 'dwell'
+            ? -5
+            : -5 + sign.progress * 18;
+      group.position.set(7.2, 4.1, phaseOffset);
       group.rotation.y = -0.12;
     },
   };