Add Tamil NER routing and WPF test harness for POC validation.

Introduce dual-script ONNX NER routing (English/Tamil/mixed), Tamil console samples and integration tests, model download scripts, and a resizable WPF MVVM harness with click-to-load prompts, batch validation, and runtime-adjustable detection panels.

src/PiiRedaction.TestHarness.Wpf/Services/ModelStatusService.cs

@@ -0,0 +1,46 @@
+using Microsoft.Extensions.Options;
+using PiiRedaction.Core.Configuration;
+using PiiRedaction.Infrastructure.Onnx;
+using PiiRedaction.TestHarness.Wpf.Models;
+
+namespace PiiRedaction.TestHarness.Wpf.Services;
+
+public sealed class ModelStatusService : IModelStatusService
+{
+    private readonly EnglishOnnxNerRunner _englishRunner;
+    private readonly TamilOnnxNerRunner _tamilRunner;
+    private readonly PiiRedactionOptions _options;
+
+    public ModelStatusService(
+        EnglishOnnxNerRunner englishRunner,
+        TamilOnnxNerRunner tamilRunner,
+        IOptions<PiiRedactionOptions> options)
+    {
+        _englishRunner = englishRunner;
+        _tamilRunner = tamilRunner;
+        _options = options.Value;
+    }
+
+    public ModelStatusSnapshot GetStatus()
+    {
+        var englishPath = OnnxAssetPathResolver.ResolveModelPath(
+            _options.EnglishOnnxModelPath,
+            _options.OnnxModelPath);
+
+        var tamilPath = OnnxAssetPathResolver.ResolveModelPath(_options.TamilOnnxModelPath);
+
+        var englishAvailability = _englishRunner.IsModelAvailable
+            ? ModelAvailability.Ready
+            : ModelAvailability.Missing;
+
+        var tamilAvailability = !_options.EnableTamilNer
+            ? ModelAvailability.Disabled
+            : _tamilRunner.IsModelAvailable
+                ? ModelAvailability.Ready
+                : ModelAvailability.Missing;
+
+        return new ModelStatusSnapshot(
+            new NerModelStatus("English", englishAvailability, englishPath),
+            new NerModelStatus("Tamil", tamilAvailability, tamilPath));
+    }
+}