fix: rewrite decoration grid to contain images within cells

The INSET overflow approach (position:absolute images extending beyond
52×52 buttons) was fundamentally broken: absolutely positioned children
don't contribute to flex row height, so rowGap controlled button-to-button
spacing but image pixels still painted into the gap, causing visual overlap
regardless of how large rowGap was set.

New approach: 72×72 circle cells, overflow:hidden, image fills the cell
via inset:0 with objectFit:contain. Gap of 16px is actual clear space
between cell edges — no math needed. Also bumped maxHeight 420→480.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/features/settings/account/ProfileDecoration.tsx

@@ -12,7 +12,7 @@ import {
 import { invalidateDecorationCache } from '../../../hooks/useAvatarDecoration';
 
 const PROFILE_FIELD = 'io.lotus.avatar_decoration';
-const INSET = 8;
+const CELL_SIZE = 72;
 
 function DecorationPreviewCell({
   slug,
@@ -34,29 +34,19 @@ function DecorationPreviewCell({
       onClick={() => onSelect(slug)}
       style={{
         position: 'relative',
-        width: 52,
-        height: 52,
+        width: CELL_SIZE,
+        height: CELL_SIZE,
         flexShrink: 0,
         border: `2px solid ${selected ? 'var(--accent-cyan)' : 'transparent'}`,
-        borderRadius: '0.75rem',
+        borderRadius: '50%',
         background: 'var(--bg-surface-variant)',
         cursor: 'pointer',
         padding: 0,
         boxShadow: selected ? '0 0 0 1px var(--accent-cyan)' : 'none',
-        overflow: 'visible',
+        overflow: 'hidden',
         outline: 'none',
       }}
     >
-      {/* Avatar placeholder tint */}
-      <div
-        style={{
-          position: 'absolute',
-          inset: 0,
-          borderRadius: '0.75rem',
-          background: 'var(--bg-surface-variant)',
-          overflow: 'hidden',
-        }}
-      />
       <img
         src={`${DECORATION_CDN}/${slug}.png`}
         alt={name}
@@ -64,10 +54,9 @@ function DecorationPreviewCell({
         decoding="async"
         style={{
           position: 'absolute',
-          top: -INSET,
-          left: -INSET,
-          width: `calc(100% + ${INSET * 2}px)`,
-          height: `calc(100% + ${INSET * 2}px)`,
+          inset: 0,
+          width: '100%',
+          height: '100%',
           objectFit: 'contain',
           pointerEvents: 'none',
         }}
@@ -149,12 +138,12 @@ export function ProfileDecoration() {
           <div
             style={{
               position: 'relative',
-              width: 52,
-              height: 52,
+              width: CELL_SIZE,
+              height: CELL_SIZE,
               flexShrink: 0,
-              borderRadius: '0.75rem',
+              borderRadius: '50%',
               background: 'var(--bg-surface-variant)',
-              overflow: 'visible',
+              overflow: 'hidden',
             }}
           >
             {selected && (
@@ -163,10 +152,9 @@ export function ProfileDecoration() {
                 alt="Selected decoration preview"
                 style={{
                   position: 'absolute',
-                  top: -INSET,
-                  left: -INSET,
-                  width: `calc(100% + ${INSET * 2}px)`,
-                  height: `calc(100% + ${INSET * 2}px)`,
+                  inset: 0,
+                  width: '100%',
+                  height: '100%',
                   objectFit: 'contain',
                   pointerEvents: 'none',
                 }}
@@ -236,7 +224,7 @@ export function ProfileDecoration() {
           direction="Column"
           gap="300"
           style={{
-            maxHeight: 420,
+            maxHeight: 480,
             overflowY: 'auto',
             paddingRight: 4,
           }}
@@ -250,12 +238,8 @@ export function ProfileDecoration() {
                 style={{
                   display: 'flex',
                   flexWrap: 'wrap',
-                  columnGap: 28,
-                  rowGap: 52,
-                  paddingBottom: INSET,
-                  paddingLeft: INSET,
-                  paddingRight: INSET,
-                  paddingTop: INSET,
+                  gap: 16,
+                  padding: 4,
                 }}
               >
                 {category.decorations.map((d) => (