C4: the conformance kit gains Passing with the words of each runner when the network did not answer; each build module's tests call it and checks/failurekit refuses one that does not (ADR 0664, issue 1748)

Claude-Session: https://claude.ai/code/session_01JG73KEq4zoDfM9WtYpcQgZ

modules/mesh-build-node/cmd/mesh-build-node/kit_test.go

@@ -2,6 +2,8 @@ package main
 
 import (
 	"context"
+	"git.novox.be/novox/mesh-catalog/modules/mesh-build-go/buildstep"
+	"strings"
 	"testing"
 	"time"
 
@@ -30,3 +32,20 @@ func TestTheStartSweepEndsWhatAPreviousProcessLeft(t *testing.T) {
 		(&Module{Node: node}).endLeftRunning(ctx, scan, before, logf)
 	})
 }
+
+// ADR 0664 §1 (issue 1748): the module's own paths from a failed fetch or install to its step's error say a network that did
+// not answer as a transport fault, and a failure of the source (a package the registry lacks) as none.
+func TestTheStepsSayAFailedNetworkAsATransportFault(t *testing.T) {
+	conformance.Passing(t, []string{conformance.GitFetch, conformance.NpmCI}, func(runner, words string) error {
+		switch runner {
+		case conformance.GitFetch:
+			run := func(context.Context, []string, string, ...string) forgekey.Ran {
+				return forgekey.Ran{Status: 128, Stderr: words}
+			}
+			return buildstep.FetchCommit(context.Background(), run, t.TempDir(), "ssh://mesh-forge/o/r.git", strings.Repeat("a", 40), "")
+		default:
+			bad := &fakeNpm{ran: forgekey.Ran{Status: 1, Stderr: words}}
+			return toolchainIn(t, bad).Ensure(context.Background(), Recipe{Steps: "k", Lock: "k"}.Version())
+		}
+	})
+}