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/Components/Modals/SettingsModal.razor.css

@@ -0,0 +1,35 @@
+.settings-modal-dialog::backdrop {
+    background: rgba(0, 0, 0, 0.5);
+}
+
+.settings-modal-dialog .modal-content {
+    max-width: 28rem;
+    margin: auto;
+}
+
+.settings-modal-dialog {
+    border: none;
+    border-radius: 0.375rem;
+    padding: 0;
+    box-shadow: 0 0.5rem 1rem rgba(0, 0, 0, 0.15);
+}
+
+.settings-modal-dialog .modal-header {
+    padding: 1rem 1.25rem;
+    border-bottom: 1px solid rgba(0, 0, 0, 0.125);
+}
+
+.settings-modal-dialog .modal-title {
+    margin: 0;
+    font-size: 1.25rem;
+}
+
+.settings-modal-dialog .modal-body {
+    padding: 1.25rem;
+}
+
+.settings-modal-dialog .modal-footer {
+    padding: 1rem 1.25rem;
+    border-top: 1px solid rgba(0, 0, 0, 0.125);
+    gap: 0.5rem;
+}