fix(themes): show store thumbnails in 16:9 (#1018)

* fix(themes): show store thumbnails in 16:9

Thumbnails are now 16:9 WebP. Render the store-row preview at 200x112
(16:9) so the screenshot isn't cropped in the grid; the lightbox already
shows it full size, now larger and crisper from the 1280x720 source.

* docs(themes): note the 16:9 thumbnail PR in the Theme Store entry

src/components/settings/ThemeStoreSection.tsx

@@ -278,11 +278,11 @@ export function ThemeStoreSection() {
                     alt=""
                     loading="lazy"
                     width={200}
-                    height={125}
+                    height={112}
                     // Offline / missing thumbnail: hide the broken-image glyph; the
                     // image's own neutral background stands in as a placeholder.
                     onError={e => { e.currentTarget.style.opacity = '0'; }}
-                    style={{ width: 200, height: 125, objectFit: 'cover', borderRadius: 6, background: 'var(--bg-deep)' }}
+                    style={{ width: 200, height: 112, objectFit: 'cover', borderRadius: 6, background: 'var(--bg-deep)' }}
                   />
                 </button>
                 <div style={{ flex: 1, minWidth: 0, display: 'flex', flexDirection: 'column', gap: 2 }}>

src/config/settingsCredits.ts

@@ -357,7 +357,7 @@ const CONTRIBUTOR_ENTRIES = [
       'Performance Probe: Monitor/Toggles redesign, live CPU/RSS/thread metrics, overlay pins and sparklines, macOS snapshots (PR #890)',
       'Performance Probe: opt-in thread-group CPU poll toggle and includeThreadGroups IPC fix (PR #891)',
       'Queue: switchable display mode — Queue (upcoming only) vs Playlist (full list), with header toggle and settings entry (PR #922)',
-      'Community Theme Store: semantic-token refactor, dedicated Themes tab with day/night scheduler, install/update/uninstall, local .zip import, and free-form community themes (safety floor + state-reactive styling); 80+ palettes moved to an on-demand CDN repo (PR #1009, #1011, #1012, #1013, #1014, #1015, #1016)',
+      'Community Theme Store: semantic-token refactor, dedicated Themes tab with day/night scheduler, install/update/uninstall, local .zip import, and free-form community themes (safety floor + state-reactive styling); 80+ palettes moved to an on-demand CDN repo (PR #1009, #1011, #1012, #1013, #1014, #1015, #1016, #1018)',
     ],
   },
   {