Merge main: renumber this branch's records around the trunk's

Both lines of work numbered from the same point, so four decision records and one design
document existed twice with different content. The trunk keeps its numbers and this branch
yields — the only rule that scales, because the trunk's are already cited by what merged
before them.

  0117 the bus is the only broker        -> 0125
  0118 a module declares its own seats   -> 0126
  0119 amqp is a provision, not the bus  -> 0127
  0120 the mesh bus is required          -> 0128
  0123 a seat carries its role's protocol -> 0129
  0124 the predecessor is ending          -> 0130
  design 29, what a module declares       -> design 32

Applied to the code repositories too, because a stale reference is worse when numbers
collide than when they dangle: the reader lands on a real record that decided something
else.

Two reconciliations the merge forced, both real:

**0110 was marked wholly superseded and was not.** Its successor says in as many words that
everything 0110 decided about what a seat *is* stands untouched — and two records that
landed on the trunk rest on exactly that part. So it is accepted again, extended rather than
replaced, with a note saying which of its claims moved and where.

**A seat's protocol becomes columns, not fields.** The trunk moved the seat set out of
compiled code into a table the controller owns. This branch had added what a role accepts,
emits and serves to the Go slice. The decision is unaffected and the mechanism is better for
it: giving a role a protocol is now a write rather than a rebuild, which is the trunk's own
argument applied to what this branch added.

One check still fails and it fails on main too: a record resting on ADR 0112 while that is
still 'proposed'. Left alone — it is not this merge's to answer.

03-DESIGN/01-to-be/23-choosing-a-provider.md

@@ -6,7 +6,7 @@ updated: 2026-09-25
 decisions:
   - 02-DECISIONS/0084-which-provider-serves-a-consumer.md
   - 02-DECISIONS/0027-a-provision-names-what-the-consumer-is-coupled-to.md
-  - 02-DECISIONS/0118-a-module-declares-its-own-seats.md
+  - 02-DECISIONS/0126-a-module-declares-its-own-seats.md
 ---
 
 # 23 — Choosing a provider
@@ -54,7 +54,7 @@ to that provider and not to whichever one is nearest.
 **A seat names the mesh's one provider of a kind.** Where a seat delivers the provision, its holder
 answers for it when several providers exist and the consumer named none. That is not picking: the
 choice was made once, mesh-wide, by assigning the holder, rather than once per consumer by naming it
-([ADR 0118](../../02-DECISIONS/0118-a-module-declares-its-own-seats.md) (superseding [ADR 0110](../../02-DECISIONS/0110-a-seat-is-a-module-assignment-from-a-closed-set.md)),
+([ADR 0126](../../02-DECISIONS/0126-a-module-declares-its-own-seats.md) (superseding [ADR 0110](../../02-DECISIONS/0110-a-seat-is-a-module-assignment-from-a-closed-set.md)),
 [26 — The seats](26-the-seats.md)). A named provider still wins over the seat, because a consumer
 coupled to particular contents has said so.