EffectiveConfig: single expand/collapse toolbar button

Replace separate Expand all / Collapse all buttons with one toggle button.
Icon and label switch based on AllSectionsExpanded (expand when any
section collapsed, collapse when all expanded).

src/DnsmasqWebUI/Components/Dnsmasq/EffectiveConfig/EffectiveConfigSection.razor

@@ -11,8 +11,13 @@
 <div class="ec-container" @onclick="DeactivateActiveFieldIfClicked">
     <OptionHelpController @ref="_optionHelpControllerRef" Visible="@_showOptionHelp" HelpKey="@_optionHelpKey" AnchorId="@_optionHelpAnchorId" Title="@_optionHelpTitle" OnCloseRequested="CloseOptionHelp" />
     <ReadonlyPopoverController @ref="_readonlyPopoverControllerRef" Visible="@_showReadonlyPopover" AnchorId="@_readonlyPopoverAnchorId" Source="@_readonlyPopoverSource" OptionName="@(_readonlyPopoverOptionName ?? "")" Value="@_readonlyPopoverValue" ManagedFilePath="@(Status?.ManagedFilePath)" OnCloseRequested="CloseReadonlyPopover" />
+    @{
+        var _sectionViews = EffectiveConfigViews.GetViewsForContext(Context);
+        var _allSectionsExpanded = _sectionViews.Count > 0 && _sectionViews.All(v => _openPanels.Contains(v.SectionId));
+    }
     <EffectiveConfigToolbar ShowSearchBox="@ShowSearchBox" SearchTerm="@_searchTerm" SearchTermChanged="@OnSearchTermChanged"
         IsEditMode="@Session.IsEditMode" PendingChangesCount="@Session.PendingChanges.Count"
+        AllSectionsExpanded="@_allSectionsExpanded"
         OnExpandAll="ExpandAll" OnCollapseAll="CollapseAll" OnEnterEditMode="EnterEditMode" OnExitEditModeWithConfirm="ExitEditModeWithConfirmAsync" OnOpenSaveModal="OpenSaveModal" />
     <CascadingValue Value="@Session">
     <CascadingValue Value="@_uiContext">

src/DnsmasqWebUI/Components/Dnsmasq/EffectiveConfig/EffectiveConfigToolbar.razor

@@ -7,11 +7,10 @@
                value="@SearchTerm" @oninput="OnSearchInput" />
     }
     <div class="ec-toolbar-actions">
-        <button type="button" class="btn btn-sm btn-outline-secondary" @onclick="OnExpandAll" title="Expand all sections" aria-label="Expand all sections">
+        <button type="button" class="btn btn-sm btn-outline-secondary" @onclick="OnToggleExpandCollapse"
-            <i class="bi bi-arrows-expand" aria-hidden="true"></i>
+                title="@(AllSectionsExpanded ? "Collapse all sections" : "Expand all sections")"
-        </button>
+                aria-label="@(AllSectionsExpanded ? "Collapse all sections" : "Expand all sections")">
-        <button type="button" class="btn btn-sm btn-outline-secondary" @onclick="OnCollapseAll" title="Collapse all sections" aria-label="Collapse all sections">
+            <i class="bi @(AllSectionsExpanded ? "bi-arrows-collapse" : "bi-arrows-expand")" aria-hidden="true"></i>
-            <i class="bi bi-arrows-collapse" aria-hidden="true"></i>
         </button>
         @if (IsEditMode)
         {
@@ -41,8 +40,17 @@
     [Parameter] public EventCallback<string> SearchTermChanged { get; set; }
     [Parameter] public bool IsEditMode { get; set; }
     [Parameter] public int PendingChangesCount { get; set; }
+    [Parameter] public bool AllSectionsExpanded { get; set; }
     [Parameter] public EventCallback OnExpandAll { get; set; }
     [Parameter] public EventCallback OnCollapseAll { get; set; }
+
+    private async Task OnToggleExpandCollapse()
+    {
+        if (AllSectionsExpanded)
+            await OnCollapseAll.InvokeAsync();
+        else
+            await OnExpandAll.InvokeAsync();
+    }
     [Parameter] public EventCallback OnEnterEditMode { get; set; }
     [Parameter] public EventCallback OnExitEditModeWithConfirm { get; set; }
     [Parameter] public EventCallback OnOpenSaveModal { get; set; }