The puck teleports on view changes; the trail never outruns it

Two owner reports. One: zoom, space switch or a tab return animated the
puck's left/top through the viewport change — it looked like the robot
driving across the whole plan. The view signature now forces the jump
class for that render, and a visibilitychange listener covers returning
to the browser tab. Two: a trail segment appeared the moment new
telemetry arrived, ahead of the still-gliding icon — the self-recorded
trail now lags exactly one point behind (the previous target is what
the puck has just reached), and an integration path is trimmed of its
live tail while moving.

demo/smoke_vacuum.mjs

@@ -56,8 +56,15 @@ const out = await page.evaluate(async () => {
     await c.updateComplete; await new Promise((r) => setTimeout(r, 30));
   }
   const trail = sr().querySelector('.vactrail polyline');
-  o.trailDrawn = !!trail && trail.getAttribute('points').split(' ').length >= 3;
+  // the trail LAGS one point behind the puck: after 3 telemetry points only
+  // the first two are drawn — a segment never outruns the icon (owner)
+  o.trailDrawn = !!trail && trail.getAttribute('points').split(' ').length === 2;
   o.trailScaledByMatrix = !!trail && trail.getAttribute('points').startsWith('300.0,400.0');
+  o.trailBehindPuck = !!trail && !trail.getAttribute('points').includes('450.0,550.0');
+  // a zoom/view change TELEPORTS the puck instead of gliding across the plan
+  c._applyView(1.35); c.requestUpdate(); await c.updateComplete;
+  o.zoomTeleports = sr().querySelector('.vacpuck').classList.contains('jump');
+  c._applyView(1); c.requestUpdate(); await c.updateComplete;
   // casing pair: dark halo + light core with identical geometry — the trail
   // must survive any room fill underneath (owner 2026-07-31)
   const tcase = sr().querySelector('.vactrail .case');
@@ -137,7 +144,8 @@ checkAll(out, {
   dockedNoPuck: true, baseMarkerThere: true, puckAppears: true, puckRound: true,
   puckPlateMatchesDev: true, puck80pct: true,
   noWedge: true, iconCentred: true, baseStaysDuringCleaning: true, trailDrawn: true,
-  trailScaledByMatrix: true, trailCasing: true, trailToggleOff: true,
+  trailScaledByMatrix: true, trailBehindPuck: true, zoomTeleports: true,
+  trailCasing: true, trailToggleOff: true,
   puckGoneWhenDocked: true, trailLingers: true, hiddenNoPuck: true,
   unknownMapNoPuck: true,
   wizardDevFound: true, wizardBanner: true, wizardSavedMatrix: true,