feat: themed avatars and branding updates (#67)

## Summary

Added comprehensive avatar and branding updates across the library application:

### 🌸 Updated Main Branding
- New library-themed avatar (with playful "shh" gesture) for navigation icon
- Updated favicon and all PWA icons (10 sizes from 72x72 to 512x512)
- Added hero avatar to home page between title and subtitle
- All branding uses consistent circular styling with elegant hover effects

### 🎨 Media-Specific Avatars
Added unique themed avatars to each media list page:

- **🎮 Games**: Gaming setup with controller and LED lights (red #ff6b6b border)
- **📚 Books**: Reading in cozy library setting (brown #8b6f47 border)
- **🎵 Music**: Joyful with headphones and urban nightscape (blue #74b9ff border)
- **📺 Shows**: Relaxing with remote and theater curtains (pink #e84393 border)
- **📖 Manga**: Reading manga with shelves background (teal #00b894 border)
- **🎨 Art**: Art studio with paintbrush (yellow #fdcb6e border)

### ✨ Features
- 120x120px circular avatars with themed colour borders
- Smooth hover animations (scale + shadow effects)
- Centered hero sections at top of each list view
- Consistent styling across all media types
- Perfect integration with existing colour themes

### 📊 Technical Details
- All icons generated from source images at multiple resolutions
- Static assets served with correct MIME types
- Optimised image formats for performance
- Responsive design with proper accessibility attributes

## Test Plan

- [x] Verify navigation icon displays correctly in header
- [x] Check favicon appears in browser tabs
- [x] Test PWA icons on mobile devices
- [x] Confirm home page hero avatar renders properly
- [x] Verify all 6 media list avatars display with correct borders
- [x] Test hover animations on all avatars
- [x] Verify build succeeds
- [x] Check static assets serve with correct MIME types

🌸 Created with love by Hikari 💖

Reviewed-on: #67
Co-authored-by: Hikari <hikari@nhcarrigan.com>
Co-committed-by: Hikari <hikari@nhcarrigan.com>

apps/frontend/src/app/components/home/home.component.ts

@@ -23,6 +23,7 @@ import { Game, GameStatus, Book, BookStatus, Music, MusicType, Manga, MangaStatu
     <div class="container">
       <div class="hero">
         <h1>Welcome to Naomi's Library</h1>
+        <img src="/assets/nav-icon.jpg" alt="Naomi's avatar" class="hero-avatar" />
         <p class="tagline">A personal collection of games, books, music, manga, shows, and art</p>
       </div>
 
@@ -190,10 +191,28 @@ import { Game, GameStatus, Book, BookStatus, Music, MusicType, Manga, MangaStatu
 
     .hero h1 {
       font-size: 2.5rem;
-      margin-bottom: 0.5rem;
+      margin-bottom: 1rem;
       color: var(--witch-purple);
     }
 
+    .hero-avatar {
+      width: 150px;
+      height: 150px;
+      border-radius: 50%;
+      object-fit: cover;
+      border: 4px solid var(--witch-lavender);
+      box-shadow: 0 4px 12px var(--witch-shadow);
+      margin: 1rem auto;
+      display: block;
+      transition: all 0.3s;
+    }
+
+    .hero-avatar:hover {
+      transform: scale(1.05);
+      box-shadow: 0 8px 16px rgba(157, 78, 221, 0.5);
+      border-color: var(--witch-rose);
+    }
+
     .tagline {
       font-size: 1.2rem;
       color: var(--witch-plum);