fix(ndi): match the NDI 6 WIN64 runtime banner in version probe

Shipping NDI 6 reports its version as a build banner of the form

    NDI SDK WIN64 13:07:00 Jun  2 2025 6.2.0.3

not the 'NDI SDK for Windows v6.x.x.x' format the prefix constant assumed. As a result NdiRuntimeProbe raised a spurious mismatch alert on every supported install. Update ExpectedRuntimeVersionPrefix to 'NDI SDK WIN64' which is the stable architecture token in the new banner; the trailing four-part version remains available for a stricter major-version check if that becomes useful.

src/TeamsISO.Engine.NdiInterop/NdiVersion.cs

@@ -12,9 +12,14 @@ public static class NdiVersion
     public const string SdkFamily = "NDI 6";
 
     /// <summary>
-    /// Prefix of the runtime version string we expect (NDI runtime reports e.g.
-    /// "NDI SDK for Windows v6.0.1.0"). Any major change of the leading "v6" is treated
-    /// as a mismatch.
+    /// Prefix of the runtime version banner we expect. The shipping NDI 6 runtime
+    /// reports its version as a build banner of the form
+    ///   "NDI SDK WIN64 13:07:00 Jun  2 2025 6.2.0.3"
+    /// where the architecture token ("WIN64" / "WIN32") is stable across patch
+    /// releases and confirms we loaded the binary the engine P/Invokes against
+    /// (Processing.NDI.Lib.x64.dll). The trailing four-part token is the SDK's
+    /// numeric version. The probe checks this prefix; a stricter probe could
+    /// additionally enforce the leading "6." in the trailing version token.
     /// </summary>
-    public const string ExpectedRuntimeVersionPrefix = "NDI SDK for Windows v6";
+    public const string ExpectedRuntimeVersionPrefix = "NDI SDK WIN64";
 }