Hosts UX, effective names, JS interop, domain UI

- Hosts: delete confirmation modal, shift range select, keyboard shortcuts,
  effective-name suffix tooltips, conditional modern header actions
- Align EffectiveNames on rows with scoped domain= + pending preview;
  unified hosts API uses full DomainValues from config snapshot
- Harden Blazor JS interop (safe helpers, IAsyncDisposable, disposal order)
- Effective config: domain multi-value display/editor, parsers, tests
- Misc: docs/testdata/docker script updates

src/DnsmasqWebUI/Components/EffectiveConfig/Common/CopyableCodeLine.razor

@@ -1,4 +1,5 @@
 @namespace DnsmasqWebUI.Components.EffectiveConfig
+@using DnsmasqWebUI.Extensions.Interop
 @inject IJSRuntime JSRuntime
 
 <div class="d-flex align-items-center gap-1 @CssClass">
@@ -15,13 +16,7 @@
     private async Task CopyAsync()
     {
         if (string.IsNullOrEmpty(Text)) return;
-        try
-        {
-            await JSRuntime.InvokeVoidAsync("copyToClipboard", Text);
-        }
-        catch
-        {
-            // Clipboard not available or failed
-        }
+        // window.copyToClipboard from wwwroot/js/copy-to-clipboard.js; swallow disconnect / clipboard failures.
+        await JSRuntime.InvokeVoidAsyncSafe("copyToClipboard", args: new object?[] { Text });
     }
 }