Move projects to src; add Neutrino secret

src/RecNet.Application/Common/Interfaces/IPlatformAuthValidator.cs

@@ -0,0 +1,14 @@
+using RecNet.Application.Common.PlatformAuth;
+using RecNet.Domain.Common;
+
+namespace RecNet.Application.Common.Interfaces;
+
+public interface IPlatformAuthValidator
+{
+    PlatformType PlatformType { get; }
+
+    Task<PlatformAuthResult> ValidateAsync(
+        string platformAuthentication,
+        string platformId,
+        CancellationToken ct = default);
+}