Renumber the records 1 to 23

The consolidation left a sparse sequence -- 1, 4, 6, 7, 9, 10, 12, 15, 16, 18,
19, 25, 34, 35, 36, 37, 40, 42, 44, 45, 48, 49, 58 -- where the gaps were only
the archaeology of what used to be there.

Renumbered contiguously. Renames run in ascending order, so every target number
is already free and no two files ever collide.

The reference rewrite is one simultaneous pass rather than a sequence of
replacements. Numbers moved into slots other numbers were vacating -- the node
host went 37 to 16 while the lab went 16 to 9 -- so replacing one at a time
would have cascaded and silently pointed things at the wrong record.

Seven plain-text references survived the merges as prose rather than links,
naming records that no longer existed: the enrolment token, the link boundary,
what a declaration is, reachability, the repository structure. Each mapped to
the consolidated record that now holds it.

Verified rather than assumed: every [ADR NNNN](path) link now has matching text
and target, checked across the whole repository, and the checker passes.

Frontmatter `consolidates:` lists dropped -- they named records that are gone,
and each consolidated record already says in prose what it absorbed.

02-DECISIONS/README.md

@@ -15,7 +15,7 @@ The records run in the order the decisions were taken, oldest first.
 
 **Every decision is a record.** There is no ledger and no index file — if a decision is worth
 recording it is worth a record, and if it is not worth a record it is not recorded
-([ADR 0019](0019-how-this-repository-works.md)). A "decision" small enough to be one line is
+([ADR 0011](0011-how-this-repository-works.md)). A "decision" small enough to be one line is
 almost always a **rule**, and a rule belongs in
 [`00-META/how-we-build.md`](../00-META/how-we-build.md), where it is enforced and keeps the
 incident that earned it.