Refactor trail management in app.js to streamline code and improve performance

- Removed unused variables and functions related to trail management, including `clearTrail`, `flushTrailPoly`, and `appendTrail`.
- Simplified icon angle calculation logic for better readability.
- Updated the rendering logic to eliminate the boat trail polyline, enhancing overall performance.

app.js

@@ -49,6 +49,7 @@
   var trajLine = null
   var boatTrail = null
   var bearingLine = null
+
   var anchorSOuter = null
   var anchorS = null
   var anchorEOuter = null
@@ -167,6 +168,7 @@
     prevDetectedStreak = prevBlindStreak = prevVisible = null
   }
 
+
   function clearTrail(resetIconAngle) {
     trailFlat.length = 0
     if (resetIconAngle !== false) lastTrailIconAngle = NaN
@@ -248,6 +250,7 @@
     camDot.setAttribute('stroke', rgba(C.pr, 0.5))
     trajLine.setAttribute('stroke', rgba(C.dr, 0.25))
     bearingLine.setAttribute('stroke', rgba(C.dr, 0.12))
+    if (boatTrail) boatTrail.setAttribute('stroke', rgba(C.dr, 0.55))
     for (var i = 0; i < 4; i++) camCorners[i].setAttribute('stroke', rgba(C.pr, 0.5))
     anchorSOuter.setAttribute('stroke', rgba(C.dr, 0.72))
     anchorS.setAttribute('fill', rgba(C.dr, 0.52))
@@ -257,16 +260,12 @@
     anchorE.setAttribute('stroke', rgba(C.wr, 0.42))
     anchorSLabel.setAttribute('fill', rgba(C.dr, 0.88))
     anchorELabel.setAttribute('fill', rgba(C.wr, 0.88))
-    if (boatTrail) boatTrail.setAttribute('stroke', rgba(C.dr, 0.55))
   }
 
   function updateTrackSvgGeomIfNeeded() {
     if (boatStart.x === lastTrackSx && boatStart.y === lastTrackSy &&
         boatEnd.x === lastTrackEx && boatEnd.y === lastTrackEy) return
-    if (!isNaN(lastTrackSx) &&
-        (boatStart.x !== lastTrackSx || boatStart.y !== lastTrackSy ||
-          boatEnd.x !== lastTrackEx || boatEnd.y !== lastTrackEy))
-      clearTrail()
+    if (!isNaN(lastTrackSx)) clearTrail()
     lastTrackSx = boatStart.x
     lastTrackSy = boatStart.y
     lastTrackEx = boatEnd.x
@@ -658,6 +657,8 @@
     var by = boatStart.y + (boatEnd.y - boatStart.y) * boatT
     var visible = isBoatVisible(bx, by, camHeading, p.fov)
     var distThisFrame = p.boatSpeed * 0.514 * dt
+    if (coneEl && SCALE > 0 && pathLen > 0.001 && !visible) appendTrail(bx, by)
+
     if (prevVisible !== null && visible !== prevVisible) {
       if (visible) {
         clearTrail(false)
@@ -674,8 +675,6 @@
     else blindStreak += distThisFrame
     prevVisible = visible
 
-    if (coneEl && SCALE > 0 && pathLen > 0.001 && !visible) appendTrail(bx, by)
-
     if (!coneEl || SCALE === 0) updateStats(p, bx, by, visible)
     else {
       draw(p, bx, by, visible)

style.css

@@ -205,47 +205,6 @@ body {
   user-select: none;
 }
 
-/* Draggable anchor affordance — discrete pulse; opacity stacks with fill/stroke alphas from JS. */
-@keyframes drag-anchor-ring-pulse {
-  0%, 100% { opacity: 0.8; }
-  50% { opacity: 1; }
-}
-
-@keyframes drag-anchor-core-pulse {
-  0%, 100% { opacity: 0.9; }
-  50% { opacity: 1; }
-}
-
-@keyframes drag-anchor-label-pulse {
-  0%, 100% { opacity: 0.84; }
-  50% { opacity: 1; }
-}
-
-#canvas-wrap svg .drag-anchor-ring {
-  animation: drag-anchor-ring-pulse 2.75s ease-in-out infinite;
-}
-
-#canvas-wrap svg .drag-anchor-ring--end,
-#canvas-wrap svg .drag-anchor-core--end,
-#canvas-wrap svg .drag-anchor-label--end {
-  animation-delay: 1.38s;
-}
-
-#canvas-wrap svg .drag-anchor-core {
-  animation: drag-anchor-core-pulse 2.75s ease-in-out infinite;
-}
-
-#canvas-wrap svg .drag-anchor-label {
-  animation: drag-anchor-label-pulse 2.75s ease-in-out infinite;
-}
-
-@media (prefers-reduced-motion: reduce) {
-  #canvas-wrap svg .drag-anchor-ring,
-  #canvas-wrap svg .drag-anchor-core,
-  #canvas-wrap svg .drag-anchor-label {
-    animation: none;
-  }
-}
 
 /* ── Zoom bar ────────────────────────────────────────── */