feat: improved layout, removed htmx-boost for simplicity

templates/_partials/_loading_indicator.html.twig

@@ -0,0 +1,4 @@
+<div class="invisible fixed top-0 left-0 inset-0 z-10 bg-white/90 flex items-center justify-center"
+        {{ stimulus_target('loading', 'indicator') }}>
+    {% include '_partials/_spinner.html.twig' with { 'class': 'w-8 h-8'} %}
+</div>