replace client-side tab toggling with server-side tab routing

Each settings tab is now a separate page load via ?tab= query param.
Flask renders only the active panel - no CSS or JS visibility logic needed.
Tab bar uses <a> links instead of buttons. Eliminates the display:none
cascade issue that was preventing Import and Maintenance tabs from showing.

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

app/main.py

@@ -594,7 +594,11 @@ def artist_gallery(artist_name):
 
 @main.route('/settings')
 def settings():
-    return render_template('settings.html')
+    valid_tabs = {'overview', 'import', 'maintenance'}
+    tab = request.args.get('tab', 'overview')
+    if tab not in valid_tabs:
+        tab = 'overview'
+    return render_template('settings.html', active_tab=tab)
 
 
 # ----------------------------

app/static/style.css

@@ -1233,6 +1233,8 @@ header {
 }
 
 .settings-tab-btn {
+  display: inline-block;
+  text-decoration: none;
   padding: 0.4rem 1.1rem;
   border-radius: 999px;
   border: 1px solid var(--filter-border);
@@ -1253,12 +1255,8 @@ header {
   color: var(--filter-active-fg);
 }
 
-/* Settings tab panels */
+/* Settings tab panels — always visible, server renders only the active one */
 .settings-tab-panel {
-  display: none;
-}
-
-.settings-tab-panel.is-active {
   display: block;
 }
 

app/templates/settings.html

@@ -6,13 +6,14 @@
 
 <!-- Tab bar -->
 <div class="settings-tab-bar" role="tablist">
-  <button class="settings-tab-btn is-active" data-tab="overview" role="tab">Overview</button>
-  <button class="settings-tab-btn" data-tab="import" role="tab">Import</button>
-  <button class="settings-tab-btn" data-tab="maintenance" role="tab">Maintenance</button>
+  <a class="settings-tab-btn{% if active_tab == 'overview' %} is-active{% endif %}" href="{{ url_for('main.settings', tab='overview') }}">Overview</a>
+  <a class="settings-tab-btn{% if active_tab == 'import' %} is-active{% endif %}" href="{{ url_for('main.settings', tab='import') }}">Import</a>
+  <a class="settings-tab-btn{% if active_tab == 'maintenance' %} is-active{% endif %}" href="{{ url_for('main.settings', tab='maintenance') }}">Maintenance</a>
 </div>
 
 <!-- ===== OVERVIEW TAB ===== -->
-<div class="settings-tab-panel is-active" data-tab="overview">
+{% if active_tab == 'overview' %}
+<div class="settings-tab-panel" data-tab="overview">
 
 <!-- System Stats (Full Width at Top) -->
 <div class="settings-grid-full">
@@ -212,8 +213,10 @@
 </div>
 
 </div><!-- end overview tab panel -->
+{% endif %}
 
 <!-- ===== IMPORT TAB ===== -->
+{% if active_tab == 'import' %}
 <div class="settings-tab-panel" data-tab="import">
 <div class="settings-grid-full">
 <div class="settings-two-col">
@@ -409,8 +412,10 @@
 </div><!-- end settings-two-col -->
 </div><!-- end settings-grid-full -->
 </div><!-- end import tab panel -->
+{% endif %}
 
 <!-- ===== MAINTENANCE TAB ===== -->
+{% if active_tab == 'maintenance' %}
 <div class="settings-tab-panel" data-tab="maintenance">
 <div class="settings-grid-full">
   <div class="settings-container">
@@ -434,6 +439,7 @@
   </div>
 </div>
 </div><!-- end maintenance tab panel -->
+{% endif %}
 
 <style>
   .clickable-stat {
@@ -1847,28 +1853,4 @@ document.addEventListener('DOMContentLoaded', () => {
 });
 </script>
 
-<script>
-(function() {
-  const tabBtns = document.querySelectorAll('.settings-tab-btn');
-  const tabPanels = document.querySelectorAll('.settings-tab-panel');
-  const validTabs = ['overview', 'import', 'maintenance'];
-
-  function activateTab(tabName) {
-    tabBtns.forEach(function(btn) {
-      btn.classList.toggle('is-active', btn.dataset.tab === tabName);
-    });
-    tabPanels.forEach(function(panel) {
-      panel.style.display = panel.dataset.tab === tabName ? 'block' : 'none';
-    });
-    history.replaceState(null, '', '#' + tabName);
-  }
-
-  tabBtns.forEach(function(btn) {
-    btn.addEventListener('click', function() { activateTab(btn.dataset.tab); });
-  });
-
-  const hash = window.location.hash.replace('#', '');
-  activateTab(validTabs.includes(hash) ? hash : 'overview');
-})();
-</script>
 {% endblock %}