Raise no condition for a take-in, a layout or a put cut by a cancellation (issue 1945)

Thirty urgent fingerprint-not-composed conditions were live on 2026-10-25, each a
done key's take-in a stop or a restart cut with "context canceled". A
cancellation is no fault of the build, the chain or the bucket: a take-in or a
layout whose controller stops returns and the next one does it; one whose own
step was cancelled is tried again without a condition; a send cut by a
cancellation counts as no failure to put its files.

The put test now starts and leaves the node's failure count at nothing, so a
second run of it (-count=2) finds no count left by the first.

cmd/mesh-controller/chain.go

@@ -80,7 +80,11 @@ func layBuildsOutSoon(ctx context.Context, inv *inventory.Inventory) {
 			Source: "chain", Summary: "the builds are not laid out under their modules, so none is read: "}
 		if err != nil {
 			fmt.Printf("chain: the builds are not laid out under their modules, and none is read until they are: %v\n", err)
-			if keeper := conditionsFrom; keeper != nil && !failed {
+			if ctx.Err() != nil {
+				return // stopped: the next controller lays them out
+			}
+			// A cancelled layout is tried again and raises nothing: a cancellation is no fault of the chain (issue 1945).
+			if keeper := conditionsFrom; keeper != nil && !failed && !errors.Is(err, context.Canceled) {
 				o.Summary += err.Error()
 				if _, oerr := keeper.Observe(ctx, o); oerr == nil {
 					failed = true