Answer the review of hq issues 348 and 349: gaps, parts, the newest merge in any state

- A reopened fault keeps its gaps: it was there at a send unless the send
  fell in one, so a send that breaks a machine recovered before it still
  fails its gate (A2).
- An undecided part holds only the conditions that name it (A4).
- D2 holds a silent resolver for the next run again, refused or not: a
  burst of refusals is also a restart (A3).
- A late merge is planned at the newest planned merge of its branch in any
  state, not only an open one (A1); merge times to the nanosecond (A5).

cmd/mesh-controller/upgrades.go

@@ -318,6 +318,21 @@ func (f following) SourceMoved(ctx context.Context, m link.SourceMoved) error {
 		return notNow(err)
 	}
 
+	// **A merge older than the newest planned merge of its branch is planned at that merge's commit**
+	// (novox/hq issue 349): the catch-up acts on a merge the bus did not hand over after the merges that
+	// came after it, and planned at its own commit it built what a later merge had fixed — the forge's
+	// security fix, on 2026-10-09 — from the commit before it, dependents and all. The later commit contains
+	// this merge's change. Planned there, with that merge's time, a module the later merge already looked at
+	// reads as history and is not built again; the rest are built from the newest commit.
+	newest, known, err := inv.NewestMergeOf(ctx, m.Owner+"/"+m.Repo, m.Base)
+	if err != nil {
+		return notNow(err)
+	}
+	if known && laterOnTheBranch(m, newest) {
+		fmt.Printf("  %s/%s %.8s was merged before %.8s (%s, %s): what it moved is built from %.8s, which "+
+			"contains it\n", m.Owner, m.Repo, m.Commit, newest.Commit, newest.ID, newest.State, newest.Commit)
+		m.Commit, m.MergedAt = newest.Commit, newest.Merged.Format(time.RFC3339Nano)
+	}
 	from, packaging, already := mergeCandidates(m, entries, read)
 	if len(from) == 0 && len(packaging) == 0 {
 		// "Already built from it" and "nothing reads it" are different facts, and reading the first
@@ -345,20 +360,6 @@ func (f following) SourceMoved(ctx context.Context, m link.SourceMoved) error {
 				e.Manifest.Module, m.Owner, m.Repo, e.Source.Ref, m.Base)
 		}
 	}
-	// **A merge older than an open plan of its branch is planned at that plan's commit** (novox/hq issue
-	// 349): the catch-up acts on a merge the bus did not hand over after the merges that came after it,
-	// and planned at its own commit it built what the later merge had fixed from the commit before the fix.
-	// The later commit contains this merge's change, so what this merge moved is built from there, and the
-	// plan made here supersedes that one as any newer plan does.
-	if open, err := inv.OpenPlans(ctx); err == nil {
-		if newest, later := newestOnTheBranch(m, open); later {
-			fmt.Printf("  %s/%s %.8s was merged before %.8s, which %s is planning: what it moved is built "+
-				"from %.8s, which contains it\n", m.Owner, m.Repo, m.Commit, newest.Commit, newest.ID, newest.Commit)
-			m.Commit, m.MergedAt = newest.Commit, newest.Merged.Format(time.RFC3339)
-		}
-	} else {
-		return notNow(err)
-	}
 	touched, added, _ := touchedBy(from, entries, m)
 	// **A module the merge deleted is not built** (novox/hq ADR 0236): its manifest is gone, so the build
 	// seat finds nothing saying what it is, and the plan failed on it (`has no module.json at …`) with