A module composed as what runs of it serves its tools as they run, so the runtime no longer drops it (issue 1126)

After the take-over of placement on 2026-10-29, shanks's runtime stopped serving the folded systemd-resolved (the
node-resolver seat's verbs answer "nothing serves") and novox's the folded nats. Neither has a want: each runs inside
its node's own composition at a build of the old form (Scope.InOwn), and is composed as Carried of the indexer's
manifest. That manifest is the catalogue's, which no build resolved, so it has no bundles (catalogue/build.go: Bundles
are set only by a build's resolution), and the runtime's MESH_TOOL_MODULES and MESH_TOOL_ENV are made from bundles
(catalogue/runtime.go). The controller composed them from the resolved manifest its store kept.

The kind: a module composed as what runs of it (Stub, Carried: held, or folded at an old build) contributes to the
others from its manifest, not from what runs. For a held module with a new build it is the other way round: its new
bundles are served, which were never delivered.

- The quick fix: read the old-form build's resolved manifest for a folded module. One instance; a held module still
  hands its new bundles.
- The thorough fix, chosen: compose.ToolsRunning reads what the node's runtime serves as it runs (its process's
  MESH_TOOL_MODULES and MESH_TOOL_ENV, each bundle's archive), frombus gives it as Node.RunsTools, and every stubbed
  module of the machine's runtime (held or carried) contributes those bundles, whatever its manifest says.

Tests: two rows (folded, held) added to TestCompositionsAreTheDeclarationSplitByModule; no new test function.

go/compose/input.go

@@ -210,6 +210,12 @@ type Node struct {
 	// (RunsOwn), folded or leaving the fold, is carried there as it runs, whatever its manifest names, so the node's own
 	// never drops it.
 	Held map[string]bool
+	// RunsTools is, by module, the tools bundles the node's runtime serves of it as it runs (ToolsRunning of what the
+	// node runs); nil when not known. A module composed as what runs of it (its Stub or Carried: held, or folded at a
+	// build of the old form) contributes these to the runtime, never its manifest's: a manifest no build resolved has no
+	// bundles, and a held module's new build's bundles are not delivered (issue 1126, 2026-10-29: shanks's runtime lost
+	// the folded systemd-resolved, novox's the folded nats).
+	RunsTools map[string][]catalogue.Bundle
 }
 
 // Place is where a node is, as its placement says (inv.Overlay).