Add agent guidance and fix lint

AGENTS.md

@@ -0,0 +1,30 @@
+# AGENTS.md
+
+## Project map
+
+- Orchard is a Go orchestration system for Tart-backed VMs.
+- `internal/controller/` owns the API surface, scheduling, SSH server, and exec/session coordination.
+- `internal/worker/` owns worker-side RPC handling and VM lifecycle integration.
+- `pkg/client/` and `pkg/resource/v1/` are the public client/resource packages.
+- `api/openapi.yaml` documents the REST API.
+- `rpc/` contains protobuf definitions plus generated Go output.
+
+## Local workflow
+
+- Format Go changes with `gofmt`.
+- Run targeted tests while iterating, then prefer `go test ./...` before shipping when the host environment supports it.
+- Lint with the repository configuration in `.golangci.yml`, for example:
+  - `golangci-lint run`
+  - or `go run github.com/golangci/golangci-lint/v2/cmd/golangci-lint@latest run`
+- Some integration tests require macOS VM support and may not be portable to every development host; when possible, add synthetic coverage for controller/worker behavior as well.
+
+## Generated code
+
+- If you change files under `rpc/*.proto`, run `buf generate` from the repository root and commit the regenerated outputs.
+- Keep API behavior changes aligned with `api/openapi.yaml`.
+
+## Change guidance
+
+- Prefer small, behavior-focused changes that keep controller and worker protocol expectations in sync.
+- When touching `/exec`, port-forwarding, or reconnectable session behavior, cover both lifecycle cleanup and concurrent access paths.
+- Preserve public API compatibility unless the change explicitly calls for an API revision.

internal/tests/exec_ssh_server_test.go

@@ -25,10 +25,6 @@ type execSSHServer struct {
 	wg sync.WaitGroup
 }
 
-func startExecSSHServer(t *testing.T, rejectFirstConnections int32) *execSSHServer {
-	return startExecSSHServerWithSessionGate(t, rejectFirstConnections, nil)
-}
-
 func startExecSSHServerWithSessionGate(
 	t *testing.T,
 	rejectFirstConnections int32,