Refactor: Bootstrap 5.3.8, Bootstrap Icons, Client/Http/Configuration layout

- Update Bootstrap to 5.3.8, add Bootstrap Icons; replace custom SVGs
- Fix settings modal: load editing state only when modal opens (avoid refresh overwrite)
- Home: StatusSection and LogsSection components with own timers
- Move HTTP clients under Client/Http with Abstractions namespace pattern
- Rename Options to Configuration; remove empty Options dir
- Components: Modals/, Home/; consistent Abstractions (Services, Client.Services, Client.Http)

src/DnsmasqWebUI/Client/Http/HostsClient.cs

@@ -0,0 +1,26 @@
+using DnsmasqWebUI.Client.Http.Abstractions;
+using DnsmasqWebUI.Models;
+using System.Net.Http.Json;
+
+namespace DnsmasqWebUI.Client.Http;
+
+public sealed class HostsClient : IHostsClient
+{
+    private readonly HttpClient _http;
+
+    public HostsClient(HttpClient http) => _http = http;
+
+    public async Task<IReadOnlyList<HostEntry>> GetHostsAsync(CancellationToken ct = default)
+    {
+        var list = await _http.GetFromJsonAsync<List<HostEntry>>("api/hosts", ct);
+        return list ?? new List<HostEntry>();
+    }
+
+    public async Task<SaveWithReloadResult> SaveHostsAsync(IReadOnlyList<HostEntry> entries, CancellationToken ct = default)
+    {
+        var response = await _http.PutAsJsonAsync("api/hosts", entries, ct);
+        response.EnsureSuccessStatusCode();
+        return await response.Content.ReadFromJsonAsync<SaveWithReloadResult>(ct)
+            ?? throw new InvalidOperationException("Unexpected null from api/hosts.");
+    }
+}