Give each pending assignment its own condition, and keep a raised row until it clears

Second review of #150: one key per machine and module let a newer failure
be cleared in the tick that raised it, pruning could orphan an open
condition, and a build no longer waited for read as never asked although it
may still run.

cmd/mesh-controller/build.go

@@ -415,16 +415,22 @@ func recordAsked(ctx context.Context, r inventory.BuildRequest) {
 	recordBuildRequest(ctx, open.inventory, r)
 }
 
-// markNotAsked says a kept build request was not handed over, or not waited for.
-func markNotAsked(ctx context.Context, id string, why error) {
+// markWaitFailed says what became of a kept build request whose waited ask failed: never handed over, so
+// nothing runs; or handed over and no longer waited for, so asked with its outcome unknown — still read as in
+// flight until its outcome or its bound (novox/hq issue 325).
+func markWaitFailed(ctx context.Context, id string, why error) {
 	open, err := openStores(ctx)
 	if err != nil {
-		fmt.Fprintf(os.Stderr, "build %s could not be marked as not asked: %v\n", id, err)
+		fmt.Fprintf(os.Stderr, "build %s could not be marked: %v\n", id, err)
 		return
 	}
 	defer open.Close()
-	if err := open.inventory.MarkNotAsked(ctx, id, why.Error()); err != nil {
-		fmt.Fprintf(os.Stderr, "build %s could not be marked as not asked: %v\n", id, err)
+	mark := open.inventory.MarkOutcomeUnknown
+	if errors.Is(why, link.ErrNotHandedOver) {
+		mark = open.inventory.MarkNotAsked
+	}
+	if err := mark(ctx, id, why.Error()); err != nil {
+		fmt.Fprintf(os.Stderr, "build %s could not be marked: %v\n", id, err)
 	}
 }
 
@@ -518,15 +524,15 @@ func buildOneAsked(ctx context.Context, source buildSource, path, ref string, wa
 		return request.ID, nil
 	}
 
-	// Waited for: kept while it is waited for, since that can take minutes, and marked when the hand-over or
-	// the wait failed — an outcome heard later is still the last word.
+	// Waited for: kept while it is waited for, since that can take minutes, and marked when the hand-over
+	// failed (not asked) or the wait did (asked, outcome unknown) — an outcome heard later is the last word.
 	if keep {
 		recordAsked(ctx, asked)
 	}
 	result, err := ask.Submit(ctx, request, wait)
 	if err != nil {
 		if keep {
-			markNotAsked(ctx, request.ID, err)
+			markWaitFailed(ctx, request.ID, err)
 		}
 		return request.ID, err
 	}