Fix category selector highlighting to use slug comparison

Use top_slug/sub_slug directly instead of current_local_href for
active state detection. The previous approach compared full request
paths against short category-relative paths, which never matched.
This also avoids conflicting with current_local_href used by brand
filter URL construction.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

browser/templates/_types/browse/desktop/_category_selector.html

@@ -2,7 +2,7 @@
 <nav aria-label="Categories"
      class="rounded-xl border bg-white shadow-sm min-h-0">
   <ul class="divide-y">
-    {% set top_active = (current_local_href == top_local_href) %}
+    {% set top_active = (sub_slug is not defined or sub_slug is none or sub_slug == '') %}
     {% set href = (url_for('market.browse.browse_top', top_slug=top_slug) ~ qs)|host %}
     <li>
       <a
@@ -19,7 +19,7 @@
     </li>
 
     {% for sub in subs_local %}
-      {% set active = (current_local_href == sub.local_href) %}
+      {% set active = (sub.slug == sub_slug) %}
       {% set href = (url_for('market.browse.browse_sub', top_slug=top_slug, sub_slug=sub.slug) ~ qs)|host %}
       <li>
         <a