Reveal a cut-off carousel item under reduced motion

Plan step 36 review of a149970d. Reduced motion writes a zero inset for
every item, so isMasked() never called one partly shown and a press on
an item the row cut off did nothing. It now reads the item's box against
the scrollport there, as it already did for multi-aspect, and the
browser test the rewrite added to document the gap asserts the reveal
instead (plan step 32's owed test).

A focused item's inset ring is 3px in again: Tailwind's
-outline-offset-3 is 3px, not the 12px the rewrite wrote.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9

resources/css/components/carousel-item.css

@@ -12,8 +12,9 @@
  *
  * The item renders the shared `md-focus-ring` class (foundation/interaction.css) rather than a
  * hand-rolled ring — the box the class draws *is* the item's own whole hit area — refined here to
- * an inset ring: an item sits edge to edge with its neighbours in the row, so the class's own 2px
- * *outward* offset would draw under the next item instead of around this one.
+ * an inset ring, 3px in, its own width (the old `focus-visible:-outline-offset-3`): items sit 8px
+ * apart with the row clipping them, so the class's own 2px *outward* offset would be cut off at the
+ * row's edges and crowd the next item.
  *
  * Full-screen: edge to edge, no corner, no mask — `--material-carousel-shift`/`-inset` go unread.
  * Multi-aspect: the view writes the item's own `aspect-ratio` inline (`aspect`, a prop, held
@@ -40,7 +41,7 @@
     }
 
     [data-md-carousel-item]:focus-visible {
-        outline-offset: -12px;
+        outline-offset: -3px;
     }
 
     [data-md-carousel='full-screen'] > [data-md-carousel-scroller] > [data-md-carousel-item] {

resources/js/carousel.js

@@ -26,7 +26,8 @@
  * Under reduced motion the buttons and keys scroll instantly and nothing is masked at all: M3
  * says the parallax goes and items "should no longer expand as they come into view — all items
  * are the same size", so every item stays at the strategy's large size and the keylines only
- * decide where the row snaps.
+ * decide where the row snaps. An item is then "not fully open" when the row cuts it off, so a
+ * press or focus on it still brings it into view.
  *
  * ---------------------------------------------------------------------------------------
  * Keyline maths ported from androidx (https://github.com/androidx/androidx), commit
@@ -1218,8 +1219,10 @@ document.addEventListener('alpine:init', () => {
                     return Math.abs(state.snaps[index] - this.scrollOffset()) > 1
                 }
 
-                // Nothing masks a multi-aspect item, so "not fully open" is "cut off by the row".
-                if (state.measured) {
+                // Nothing masks a multi-aspect item, nor any item under reduced motion (render()
+                // writes a zero inset for every one), so there "not fully open" is "cut off by the
+                // row": its box reaching past the scrollport's edge.
+                if (state.measured || state.reducedMotion.matches) {
                     const row = this.$refs.scroller.getBoundingClientRect()
                     const item = state.items[index].element.getBoundingClientRect()