fix: use cameleer logo as favicon, upgrade design system to v0.1.20, fix DataTable scroll

- Replace placeholder clock favicon with cameleer camel logo SVG
- Upgrade @cameleer/design-system from v0.1.19 to v0.1.20
- Add minHeight: 0 to main element to complete flex chain for fillHeight DataTable

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ui/src/components/LayoutShell.tsx

@@ -268,7 +268,7 @@ function LayoutContent() {
         <ContentTabs active={scope.tab} onChange={setTab} scope={scope} />
       )}
 
-      <main style={{ flex: 1, display: 'flex', flexDirection: 'column', overflow: 'hidden', padding: isAdminPage ? '1.5rem' : 0 }}>
+      <main style={{ flex: 1, display: 'flex', flexDirection: 'column', overflow: 'hidden', minHeight: 0, padding: isAdminPage ? '1.5rem' : 0 }}>
         <Outlet />
       </main>
     </AppShell>