Fix getCategory to use current base instead of ref prefix

Tags are categorized by the base they belong to, not by their
ref prefix. A tag in the hst table is always a hashtag, regardless
of whether its ref starts with "flg", "ply", etc.

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

index.html

@@ -846,10 +846,7 @@ const Utils = {
   },
 
   getCategory(tag) {
-    const ref = (tag.ref || "").toLowerCase();
-    for (const cat of Object.keys(CONFIG.CATEGORIES)) {
-      if (ref.startsWith(cat)) return cat;
-    }
+    // Category is determined by the current base being viewed
     return State.get("base");
   },