feat: Swap snack icon from popcorn 🍿 to bag of chips image

Replaced the Snack category emoji with an actual chips illustration
served from static/icons/chips.png. The icon renders in the asset
list category badges as a 28x28 object-fit:contain image within
the 42x42 circular badge.

static/index.html

@@ -410,6 +410,7 @@
     .asset-item .ai-icon.cat-Utensils---Serveware { background: #2a2510; }
     .asset-item .ai-icon.cat-Equipment { background: #2a1a2e; }
     .asset-item .ai-icon.cat-Other { background: #1a1b26; }
+    .asset-item .ai-icon .cat-icon-img { width: 28px; height: 28px; object-fit: contain; }
     .asset-item .ai-info { flex: 1; min-width: 0; }
     .asset-item .ai-name { font-weight: 600; font-size: 15px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
     .asset-item .ai-meta { font-size: 12px; color: var(--text2); margin-top: 2px; }
@@ -3125,7 +3126,7 @@
     // ── Category config ───────────────────────────────────────────────────
     const CATEGORY_MAP = {
       'Bev':         { icon: '🥤', color: '#0a7ab5' },
-      'Snack':       { icon: '🍿', color: '#c97d0e' },
+      'Snack':       { icon: '<img src="icons/chips.png" class="cat-icon-img" alt="">', color: '#c97d0e' },
       'Gf bev':      { icon: '🧃', color: '#0a9e5a' },
       'Gf food':     { icon: '🥪', color: '#8a5c2a' },
       'Other':       { icon: '📦', color: '#6b7280' },