Merge main: the trunk renamed the seats and made them data

Both branches changed the seat set from the same starting point, so every number
collided and every `mesh-*` name existed twice. The trunk's numbers and names win:
this branch's records became 0129/0130 and its migrations 0037/0038, and the
hardcoded rename map gave way to the trunk's `seat_alias` table — a rename is a
row now (ADR 0122), not a recompile.

Three of my checks were wrong and the merge is what showed it:

A seat with an empty protocol is a marker, not an incomplete declaration. Most
node-scoped seats are markers — which module is this machine's packet filter —
and refusing one refused most of the set, the showcase module included. A
mistyped field name is already refused by the parser, so an empty protocol was
written as one deliberately.

A claim on a seat this manifest does not declare is not the parser's to judge. A
module may hold a seat another module declared; that is the whole reason ADR 0126
has callers name the seat and not its provider. Whether the seat exists is a fact
about the catalogue, so the refusal is at registration, where every declaration
is in view.

And a seat may share a name with the provision it delivers. `git`, the npm
registry and the artifact store still do, because renaming a delivering seat
cascades to every consumer requiring it, with a window where a holder stops
resolving mid-flight. The trunk deferred exactly those three on purpose.

Full suite green against a real NATS and store.

cmd/mesh-controller/push.go

@@ -524,8 +524,14 @@ func composeEach(names []string,
 			continue
 		}
 		if len(declared.Resources) == 0 {
-			fmt.Printf("%s is assigned nothing — skipped\n", name)
-			continue
+			// Sent, not skipped (novox/hq issue 127). A node whose declaration composes to
+			// nothing may have HELD something before — the broker opening a placement gave it,
+			// say — and skipping the empty declaration leaves that last resource in force
+			// forever, re-applied by the node's own heartbeat, with no way for the mesh to say
+			// it is gone. An empty declaration is the correction: the host drops what the mesh
+			// owned and keeps what it found (the adoption envelope still rides along). A node
+			// that never held anything applies it as the no-op it is.
+			fmt.Printf("%s owns nothing now — sent so it drops what it last held\n", name)
 		}
 		sending = append(sending, readyNode{name, declared})
 	}