Order the records the way the system is learned

Jochen asked whether the order made sense. It did not -- it followed when
things happened to be decided, which after consolidation is fictional anyway
since record 5 alone folds decisions taken across a week.

Concretely wrong before: the domain statement sat at 8, after five engineering
rules; the constitution was scattered across 5, 12 and 17; the tiers landed at
15, 16, 21 and 22 with process records in between.

Now it walks: what the mesh is (1-3), its tiers from the bottom up (4-8), what
runs on them and how it gets there (9-10), how it is built (11-16), how it is
checked (17-18), how we work (19-23).

Two things made this safe rather than free. It is a permutation, not a
compaction, so the renames go through temporary names -- otherwise two files
want one slot and one is lost. And the reference rewrite is a single
simultaneous pass, because almost every number moved into a slot another number
was vacating; replacing one at a time would have cascaded and pointed things at
the wrong record while still resolving.

Verified: 284 [ADR NNNN](path) links across the repository, all with matching
text and target.

The ordering principle is now stated in 19 rather than left implicit -- the
repository already said "the numbering is the flow" about its folders, and
there was no reason for the records to be the exception.

03-DESIGN/01-to-be/01-end-to-end-testing.md

@@ -4,9 +4,9 @@ status: in-progress
 code: [mesh-lab]
 updated: 2026-08-23
 decisions:
-  - 02-DECISIONS/0009-the-lab.md
-  - 02-DECISIONS/0009-the-lab.md
-  - 02-DECISIONS/0011-how-this-repository-works.md
+  - 02-DECISIONS/0016-the-lab.md
+  - 02-DECISIONS/0016-the-lab.md
+  - 02-DECISIONS/0019-how-this-repository-works.md
 ---
 
 # End-to-end testing
@@ -37,7 +37,7 @@ today, that is a gap in the vocabulary rather than a reason to privilege that sh
 
 The design below describes a scenario as a complete mesh — forge (Gitea), coordinator,
 delivery cascade — because what it tests is a module. **That is the larger of two classes, and
-not the first one built** ([ADR 0009](../../02-DECISIONS/0009-the-lab.md)).
+not the first one built** ([ADR 0016](../../02-DECISIONS/0016-the-lab.md)).
 
 | | **Bootstrap scenario** | **Full scenario** |
 |---|---|---|
@@ -127,7 +127,7 @@ drifts.
   a mesh named by the request instead.
 - **Scenarios must be concurrent and cheap.** Several agents working means several scenarios
   at once, each needing its own network and nodes. A lab node is a virtual machine
-  ([ADR 0009](../../02-DECISIONS/0009-the-lab.md)), and snapshots are
+  ([ADR 0016](../../02-DECISIONS/0016-the-lab.md)), and snapshots are
   what make repetition cheap — restoring a scenario costs far less than building one. The
   earlier argument here, that only system containers made this affordable, was superseded: the
   scale it assumed was invented rather than required.