fix: add missing th_sortable macro for sortable table headers

The subscription templates were importing th_sortable but the macro
didn't exist. Added the macro to tables.html with:
- Clickable header with sort indicator arrows
- Alpine.js integration for sorting state
- Visual feedback for current sort column and direction

Also removed unused empty_state import from subscription-tiers.html.

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

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

app/templates/admin/subscription-tiers.html

@@ -3,7 +3,7 @@
 {% extends "admin/base.html" %}
 {% from 'shared/macros/alerts.html' import alert_dynamic, error_state %}
 {% from 'shared/macros/headers.html' import page_header_refresh %}
-{% from 'shared/macros/tables.html' import table_wrapper, table_header_custom, th_sortable, empty_state %}
+{% from 'shared/macros/tables.html' import table_wrapper, table_header_custom, th_sortable %}
 {% from 'shared/macros/modals.html' import modal_confirm %}
 
 {% block title %}Subscription Tiers{% endblock %}

app/templates/shared/macros/tables.html

@@ -69,6 +69,65 @@
 {% endmacro %}
 
 
+{#
+  Sortable Table Header Cell (th_sortable)
+  ========================================
+  Renders a single sortable table header cell for use inside table_header_custom.
+
+  Parameters:
+    - key: The data key/column name for sorting
+    - label: Display label for the column
+    - sort_func: Alpine.js function name to call on click (default: 'sortBy')
+    - sort_order_var: Alpine.js variable for current sort order (default: 'sortOrder')
+
+  Usage:
+    {% call table_header_custom() %}
+        {{ th_sortable('name', 'Name', 'sortBy', 'sortOrder') }}
+        {{ th_sortable('created_at', 'Created', 'sortBy', 'sortOrder') }}
+        <th class="px-4 py-3">Actions</th>
+    {% endcall %}
+
+  Required Alpine.js:
+    sortBy: '',
+    sortOrder: 'asc',
+    handleSort(key) {
+        if (this.sortBy === key) {
+            this.sortOrder = this.sortOrder === 'asc' ? 'desc' : 'asc';
+        } else {
+            this.sortBy = key;
+            this.sortOrder = 'asc';
+        }
+        this.loadData();
+    }
+#}
+{% macro th_sortable(key, label, sort_func='sortBy', sort_order_var='sortOrder') %}
+<th class="px-4 py-3">
+    <button
+        @click="{{ sort_func }} = '{{ key }}'; {{ sort_order_var }} = {{ sort_func }} === '{{ key }}' && {{ sort_order_var }} === 'asc' ? 'desc' : 'asc'; loadData()"
+        class="flex items-center space-x-1 hover:text-gray-700 dark:hover:text-gray-200 transition-colors group"
+    >
+        <span>{{ label }}</span>
+        <span class="flex flex-col">
+            <svg
+                class="w-3 h-3 -mb-1 transition-colors"
+                :class="{{ sort_func }} === '{{ key }}' && {{ sort_order_var }} === 'asc' ? 'text-purple-600 dark:text-purple-400' : 'text-gray-300 dark:text-gray-600 group-hover:text-gray-400'"
+                fill="currentColor" viewBox="0 0 20 20"
+            >
+                <path d="M5 12l5-5 5 5H5z"/>
+            </svg>
+            <svg
+                class="w-3 h-3 -mt-1 transition-colors"
+                :class="{{ sort_func }} === '{{ key }}' && {{ sort_order_var }} === 'desc' ? 'text-purple-600 dark:text-purple-400' : 'text-gray-300 dark:text-gray-600 group-hover:text-gray-400'"
+                fill="currentColor" viewBox="0 0 20 20"
+            >
+                <path d="M15 8l-5 5-5-5h10z"/>
+            </svg>
+        </span>
+    </button>
+</th>
+{% endmacro %}
+
+
 {#
   Sortable Table Header
   =====================