Homepage icons: stronger shadow and dark outline for pop

Added dark outline via text-shadow and increased drop-shadow
opacity to make white icons stand out against dark background.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontends/web/templates/index.html

@@ -16,7 +16,12 @@
     font-size: 3.5rem;
     color: #fff;
     margin-bottom: 0.5rem;
-    filter: drop-shadow(0 3px 6px rgba(0, 0, 0, 0.4));
+    filter: drop-shadow(0 4px 8px rgba(0, 0, 0, 0.6));
+    text-shadow:
+        -1px -1px 0 rgba(0, 0, 0, 0.3),
+        1px -1px 0 rgba(0, 0, 0, 0.3),
+        -1px 1px 0 rgba(0, 0, 0, 0.3),
+        1px 1px 0 rgba(0, 0, 0, 0.3);
     transition: all 0.15s ease;
 }
 .home-icon span {