Initial commit: Add project files

templates/dotnet/VerticalSlice/Handler.cs.template

@@ -0,0 +1,10 @@
+namespace __MODULE__.Features.__SLICE__;
+
+public sealed class Handler(/* narrow ports only */)
+{
+    public async Task<Response> HandleAsync(Request request, string correlationId, CancellationToken ct)
+    {
+        // 1) server-side PIT context 2) idempotency 3) transaction 4) policy 5) outbox
+        throw new NotImplementedException("Complete the approved Slice Spec; do not guess missing contracts.");
+    }
+}