Builder's fetch test takes the named tree as data, not computed

The named tree is the indexer's computation (ADR 0593 §2): the builder reads it
from the module's value, so its test gives one as the indexer would write it.

Claude-Session: https://claude.ai/code/session_01NcbgfJ9Gum47zkFKWRaovL

modules/mesh-delivery-builder/internal/build/r4e_test.go

@@ -305,10 +305,9 @@ func TestTheFetchOfAModuleNamingItsPathsCarriesItsDirectoryAndThosePaths(t *test
 	r := newRig(t, tsPackage)
 	r.bm.packages["lib"] = "@novox/mesh-sdk@0.1.15"
 	paths := map[string]string{"src": hex40('1'), "package.json": hex40('2')}
-	tree, err := delivery.NamedTree(manifestD, paths)
-	if err != nil {
-		t.Fatal(err)
-	}
+	// The named tree the indexer computes from those paths (its own, ADR 0593 §2), given as data: the builder reads it,
+	// never computes it.
+	const tree = delivery.NamedTreePrefix + "5b5e0f3b6f3c1f2a9d8e7c6b5a4938271605f4e3d2c1b0a9f8e7d6c5b4a39281"
 	data, err := delivery.EncodeModule(delivery.Module{Repository: "novox/mesh-sdk", Commit: "7a74cee83f88e6585a5511c3cc53bdf0f5303d20", FP2: fp1, Manifest: manifestD, Path: ".",
 		Toolchains: agreedToolchains, Inputs2: &delivery.KeptInputs2{Tree: tree, Paths: paths}})
 	if err != nil {