EffectiveConfig section CSS/panel updates; add ConfigFileList components

src/DnsmasqWebUI/Components/EffectiveConfig/Composition/EffectiveConfigSection.razor.css

@@ -125,6 +125,22 @@
     opacity: 1;
 }
 
+/* Animated expand/collapse: grid 0fr → 1fr */
+::deep .ec-section-collapse {
+    display: grid;
+    grid-template-rows: 0fr;
+    transition: grid-template-rows 0.25s ease-out;
+}
+
+::deep .ec-section-collapse-open {
+    grid-template-rows: 1fr;
+}
+
+::deep .ec-section-collapse-inner {
+    min-height: 0;
+    overflow: hidden;
+}
+
 ::deep .ec-section-body {
     padding: 0.25rem 1rem 0.5rem 1rem;
     padding-left: 1rem;

src/DnsmasqWebUI/Components/EffectiveConfig/Composition/EffectiveConfigSectionPanel.razor

@@ -8,8 +8,9 @@
             <span class="ec-section-title fw-bold">@Title</span>
             <i class="bi @(IsOpen ? "bi-chevron-down" : "bi-chevron-right") ec-section-chevron" aria-hidden="true"></i>
         </button>
-        <div class="collapse @(IsOpen ? "show" : "")">
-            <div class="ec-section-body">
+        <div class="ec-section-collapse @(IsOpen ? "ec-section-collapse-open" : "")">
+            <div class="ec-section-collapse-inner">
+                <div class="ec-section-body">
                 <ul class="list-unstyled mb-0">
                     @foreach (var f in Descriptors)
                     {
@@ -18,6 +19,7 @@
                             IsEditMode="@IsEditMode" IsActive="@(ActiveFieldKey == fieldKey)" />
                     }
                 </ul>
+                </div>
             </div>
         </div>
     </div>