refactor: import brand icons directly from design system

Import PNGs via Vite from @cameleer/design-system/assets instead of
copying to public/. Only favicons remain in public/ (needed by HTML).

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

ui/src/components/LayoutShell.tsx

@@ -16,6 +16,7 @@ import {
   useStarred,
 } from '@cameleer/design-system';
 import type { SearchResult, SidebarTreeNode } from '@cameleer/design-system';
+import sidebarLogo from '@cameleer/design-system/assets/cameleer3-48.png';
 import { Box, Settings, FileText, ChevronRight, Square, Pause, Star, X } from 'lucide-react';
 import { useQueryClient } from '@tanstack/react-query';
 import { useRouteCatalog } from '../api/queries/catalog';
@@ -625,7 +626,7 @@ function LayoutContent() {
 
   // --- Render -------------------------------------------------------
   const camelLogo = (
-    <img src={`${config.basePath}cameleer3-logo-48.png`} alt="" style={{ width: 28, height: 28 }} />
+    <img src={sidebarLogo} alt="" style={{ width: 28, height: 28 }} />
   );
 
   const sidebarElement = (