docs: add agents instructions (#2263)

* docs: add agents instructions

* Update AGENTS.md

Author: rogeralsing

AGENTS.md

@@ -0,0 +1,7 @@
+# Agent Instructions
+
+- Install dotnet 8
+- For cluster tests to work, start the Docker Compose environment defined in `tests/Proto.Cluster.Tests/docker-compose.yml` before running tests.
+- Compile the full project before completing any task: `dotnet build ProtoActor.sln`.
+- Run the full suite of .NET tests for the solution: `dotnet test ProtoActor.sln`.
+