Restyle category tree to idiomatic Bootstrap list-group pattern (v0.1.8)

Switch from custom link classes to Bootstrap's native list-group-item-action
pattern. Replace bold primary-colored active background with subtle tertiary
background, left accent border, and semibold text.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

assets/css/wc-bootstrap.css

@@ -648,6 +648,7 @@ header.sticky-top.is-stuck {
 /* ==========================================================================
    Category Tree Sidebar
    Hierarchical product category navigation with collapsible sub-levels.
+   Uses Bootstrap list-group-item-action with subtle active styling.
    ========================================================================== */
 
 .category-tree {
@@ -658,24 +659,17 @@ header.sticky-top.is-stuck {
     background-color: transparent;
 }
 
-.category-tree-link {
-    color: var(--bs-body-color);
-    transition: background-color 0.15s ease, color 0.15s ease;
-}
-
-.category-tree-link:hover {
+/* Subtle active state: fw-semibold + left accent border instead of
+   full primary background, keeping the look understated. */
+.category-tree .list-group-item.active {
     background-color: var(--bs-tertiary-bg);
     color: var(--bs-body-color);
+    border-left: 3px solid var(--bs-primary);
+    font-weight: 600;
 }
 
-.category-tree-link.active {
-    background-color: var(--bs-primary);
-    color: #fff;
-}
-
-.category-tree-link.active .badge {
-    background-color: rgba(255, 255, 255, 0.2) !important;
-    color: #fff !important;
+.category-tree .list-group-item.active small {
+    color: var(--bs-body-secondary) !important;
 }
 
 /* Rotate chevron icon when collapsed/expanded */
@@ -686,8 +680,3 @@ header.sticky-top.is-stuck {
 .category-tree-toggle[aria-expanded="false"] .bi {
     transform: rotate(-90deg);
 }
-
-/* Nested list indentation */
-.category-tree .list-group-flush .list-group-flush {
-    padding-left: 0.75rem;
-}