Playtest #3 fixes: lost models, picking, live LP, temp overflow, 蕾缪安 S3, 回环射手, FX, detail card, spinners

- #1 lost operator models: the Spine store no longer hands out a skeleton whose unload is in flight
  (PIXI.Assets.unload is async); eviction runs 1 s after a release and the empty-scene budget only after 3 s
- #7 picking: one shared rule (render/pick.js, pixel probe where bodies overlap) for prep/battle clicks,
  hover, the enemy pen and equipment drops; the drag ghost stands on its drop tile; hover probes capped
  at one per frame
- #2 the top-bar LP drops live as the own battle's enemies enter the blue gate (−N, 联防中), teammates'
  pending LP in the team panel
- #3 temp overflow pieces that arrive after a prep deadline survive through the next prep (tempDue);
  temp-row warning and ready-button reason
- #4 蕾缪安 S3: locks every 0.5 s, then one shell every 0.3 s in lock order (PRTS notes), bombardShell fx
- #5 回环射手: real boomerang (out 15, back 3.75 tiles/s, attack only when every boomerang is caught)
- #6 visible projectiles, muzzle flashes, slashes, skill bursts and auras at unchanged frame cost
- #8 特质 right under the detail card header, with its official type icon
- #9 no spinning busy cursors / spinners next to texts; game data warmed before the match
- docs, recordings and tests updated (2414 unit tests, all browser suites green)

public/css/components.css

@@ -71,14 +71,19 @@
 
 .btn__icon { width: 1.15em; height: 1.15em; }
 .btn__label { position: relative; }
-.btn__spin {
-  width: 1em;
-  height: 1em;
-  border: 2px solid currentColor;
-  border-right-color: transparent;
-  border-radius: 50%;
-  animation: spin .7s linear infinite;
+/* a request in flight (Button `loading`): a thin bar sweeps along the bottom edge, shown only after 250 ms (quick
+   replies show nothing). Deliberately no spinning ring / wait cursor: next to text those read as "the text is still
+   loading from the server" (user playtest #3 item 9). */
+.btn__busy {
+  position: absolute; left: 0; right: 0; bottom: 0; height: 2px; overflow: hidden; pointer-events: none;
+  opacity: 0; animation: btn-busy-in 1ms linear 250ms forwards;
 }
+.btn__busy::before {
+  content: ''; position: absolute; top: 0; bottom: 0; left: 0; width: 40%;
+  background: var(--btn-bd-hover, var(--mint-400)); animation: btn-busy 1.1s var(--ease-in-out) infinite;
+}
+@keyframes btn-busy-in { to { opacity: 1; } }
+@keyframes btn-busy { from { transform: translateX(-100%); } to { transform: translateX(250%); } }
 @keyframes spin { to { transform: rotate(360deg); } }
 
 /* filled variants carry a hatch strip on the right end (in-game "准备就绪" look) */
@@ -156,7 +161,7 @@
   background-position: right center;
   background-repeat: no-repeat;
 }
-.btn.is-loading { cursor: progress; --btn-fg: var(--text-lo); }
+.btn.is-loading { cursor: default; --btn-fg: var(--text-lo); }
 .btn--primary.is-loading { --btn-bg: var(--mint-700); --btn-fg: var(--text-on-mint); }
 
 .btn--sm { height: .36rem; min-width: .36rem; padding: 0 .16rem; font-size: .15rem; gap: .07rem; }