Refactor settings modal to use ISettingsModalService and SettingsModalSections

- Replace SettingsModalContext with SettingsModalSections
- Add SettingsModalService for modal state management
- Add StatusSection.razor.css for status-dot styles
- Update layout, NavMenu, and modal components
- Update tests for config/settings changes

src/DnsmasqWebUI/Models/Client/SettingsModalContext.cs

@@ -1,19 +0,0 @@
-namespace DnsmasqWebUI.Models.Client;
-
-/// <summary>
-/// Which subset of client settings to show in the settings modal.
-/// </summary>
-public enum SettingsModalContext
-{
-    /// <summary>Show all settings with optional search.</summary>
-    All,
-
-    /// <summary>Show only service status polling interval.</summary>
-    ServicePolling,
-
-    /// <summary>Show only recent logs polling interval.</summary>
-    LogsPolling,
-
-    /// <summary>Show only DHCP leases refresh interval.</summary>
-    LeasesPolling
-}

src/DnsmasqWebUI/Models/Client/SettingsModalSections.cs

@@ -0,0 +1,55 @@
+namespace DnsmasqWebUI.Models.Client;
+
+/// <summary>
+/// Which subset of client settings to show in the settings modal.
+/// </summary>
+public enum SettingsModalContext
+{
+    /// <summary>Show all settings with optional search.</summary>
+    All,
+
+    /// <summary>Show only service status polling interval.</summary>
+    ServicePolling,
+
+    /// <summary>Show only recent logs polling interval.</summary>
+    LogsPolling,
+
+    /// <summary>Show only DHCP leases refresh interval.</summary>
+    LeasesPolling
+}
+
+/// <summary>
+/// Central definition of settings modal sections: keys, display names, field labels, and searchable text.
+/// </summary>
+public static class SettingsModalSections
+{
+    public const string ServiceStatus = "ServiceStatus";
+    public const string Logs = "Logs";
+    public const string Leases = "Leases";
+
+    /// <summary>Section metadata: display name (header), field label (for input), and searchable text for filtering.</summary>
+    public sealed record SectionMeta(string DisplayName, string FieldLabel, string SearchableText);
+
+    public static readonly IReadOnlyDictionary<string, SectionMeta> All = new Dictionary<string, SectionMeta>(StringComparer.OrdinalIgnoreCase)
+    {
+        [ServiceStatus] = new("Service status", "Polling interval (seconds)", "service status polling interval seconds"),
+        [Logs] = new("Recent logs", "Polling interval (seconds)", "recent logs polling interval seconds"),
+        [Leases] = new("DHCP leases", "Refresh interval (seconds)", "dhcp leases refresh interval seconds"),
+    };
+
+    /// <summary>Maps a focused context (single-section view) to its section key. Returns null for All.</summary>
+    public static string? GetSectionKeyForContext(SettingsModalContext context) => context switch
+    {
+        SettingsModalContext.ServicePolling => ServiceStatus,
+        SettingsModalContext.LogsPolling => Logs,
+        SettingsModalContext.LeasesPolling => Leases,
+        _ => null
+    };
+
+    public static bool MatchesSearch(string key, string searchTerm)
+    {
+        if (string.IsNullOrWhiteSpace(searchTerm)) return true;
+        if (!All.TryGetValue(key, out var meta)) return false;
+        return meta.SearchableText.Contains(searchTerm.Trim(), StringComparison.OrdinalIgnoreCase);
+    }
+}