Fix placeholder proto namespace to use project's actual namespace

The WriteProtoFileTask now receives RootNamespace and AssemblyName from
MSBuild and uses them for the placeholder proto's csharp_namespace instead
of hardcoded "Generated.Grpc". This ensures GrpcGenerator can find the
service base types on first build, enabling gRPC service registration
to work without requiring a second build.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Svrnty.CQRS.Grpc.Generators/WriteProtoFileTask.cs

@@ -39,6 +39,16 @@ public class WriteProtoFileTask : Task
     [Required]
     public string ProtoFileName { get; set; } = string.Empty;
 
+    /// <summary>
+    /// The root namespace of the project (optional, falls back to AssemblyName)
+    /// </summary>
+    public string RootNamespace { get; set; } = string.Empty;
+
+    /// <summary>
+    /// The assembly name of the project (used for proto namespace if RootNamespace not set)
+    /// </summary>
+    public string AssemblyName { get; set; } = string.Empty;
+
     public override bool Execute()
     {
         try
@@ -65,13 +75,20 @@ public class WriteProtoFileTask : Task
 
                 // Write a minimal placeholder proto file so Grpc.Tools doesn't fail
                 // The real content will be generated on the next build
-                var placeholderProto = @"syntax = ""proto3"";
+                // Use project's namespace so GrpcGenerator can find the service base types
+                var projectNamespace = !string.IsNullOrEmpty(RootNamespace) ? RootNamespace
+                    : !string.IsNullOrEmpty(AssemblyName) ? AssemblyName
+                    : "Generated";
+                var grpcNamespace = $"{projectNamespace}.Grpc";
 
-option csharp_namespace = ""Generated.Grpc"";
+                var placeholderProto = $@"syntax = ""proto3"";
+
+option csharp_namespace = ""{grpcNamespace}"";
 
 package cqrs;
 
 // Placeholder proto file - will be regenerated on next build
+// Using namespace: {grpcNamespace}
 ";
                 var placeholderOutputPath = Path.Combine(ProjectDirectory, OutputDirectory);
                 Directory.CreateDirectory(placeholderOutputPath);

Svrnty.CQRS.Grpc.Generators/build/Svrnty.CQRS.Grpc.Generators.targets

@@ -32,6 +32,8 @@
       ProjectDirectory="$(MSBuildProjectDirectory)"
       IntermediateOutputPath="$(IntermediateOutputPath)"
       OutputDirectory="$(ProtoOutputDirectory)"
-      ProtoFileName="$(GeneratedProtoFileName)" />
+      ProtoFileName="$(GeneratedProtoFileName)"
+      RootNamespace="$(RootNamespace)"
+      AssemblyName="$(AssemblyName)" />
   </Target>
 </Project>