feat: replace icons with brand assets from design-system v0.1.32

- Replace favicon SVG with official camel-logo.svg from design-system
- Add PNG favicons (32px, 192px) with proper link tags in index.html
- Replace sidebar logo with 48px brand icon (cameleer-logo-48.png)
- Replace sign-in page logo with 48px brand icon
- Permit favicon PNGs in SecurityConfig

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

ui/sign-in/src/SignInPage.tsx

@@ -56,7 +56,7 @@ export function SignInPage() {
       <Card className={styles.card}>
         <div className={styles.loginForm}>
           <div className={styles.logo}>
-            <img src="/favicon.svg" alt="" className={styles.logoImg} />
+            <img src="/cameleer-logo-48.png" alt="" className={styles.logoImg} />
             cameleer3
           </div>
           <p className={styles.subtitle}>{subtitle}</p>