Review: three ADRs no longer said what we had concluded

A sweep for claims overtaken by the last few days. Annotated rather than
rewritten, following the pattern already in 0049 -- what changed and why is the
useful part, and an accepted record should not quietly become something else.

0057's init section was wrong on all three of its claims. It said the host
needs FOUR things from an init; 0061 reduced that to one. It said every machine
the mesh targets already has systemd; Alpine does not, and it is the intended
first node. It said there is no second init to abstract over; there is now, and
the answer is still not an abstraction -- it is a four-line file per system.
What survives is the part that was always right: an init is not a dependency in
0041's sense, because it is not installed, it is what the machine already is.

0048 named Docker as the container runtime. It is now docker or podman,
detected rather than chosen -- because adoption keeps what a machine already
has, so naming one contradicted a rule already decided. That row is the only
one of the five that names two, and the record now says why.

0060 claimed the bundle is portable across operating systems. Its mechanism is;
its contents are not -- package names, unit names, service names all differ, so
an Arch host embeds an Arch bundle. That was my error, and it is the exact
confusion behind the question that found it.

The design layer had the same drift: 07 and 09 said "Docker" where they meant a
container runtime, 09 said systemd restarts the host after an upgrade when the
launcher does, and both install snippets assumed Arch. They now show Alpine and
Arch side by side, which makes the point better than prose did -- step 1
differs per system, step 2 never does.

Checked and NOT changed: 0047's "the vocabulary grows by one shape" is a claim
about the rate, not the count, and is still true. 0037 lists docker among tools
the host manages, which it does. 0041 says nothing about either.

03-DESIGN/01-to-be/07-the-substrate.md

@@ -11,6 +11,7 @@ decisions:
   - 02-DECISIONS/0047-the-bundle-may-carry-actions-the-link-may-not.md
   - 02-DECISIONS/0048-the-substrate-is-named.md
   - 02-DECISIONS/0049-a-route-is-a-grant.md
+  - 02-DECISIONS/0060-the-host-is-built-per-operating-system.md
 ---
 
 # The substrate
@@ -118,7 +119,7 @@ is what keeps the bundle small enough for a person to read and check.
 The order, from [research 011](../../01-RESEARCH/011-the-module-graph/worked-provider.md):
 
 ```
-0  Docker exists                        detected, or installed as a package
+0  a container runtime exists           detected — docker or podman — or installed
 1  PostgreSQL runs                      pulled by digest, from the bundle
 2  a database is created in it          an action, run locally
 3  the control plane's schema applied   an action, against that database
@@ -131,8 +132,13 @@ Only PostgreSQL is raised from the bundle, for the reason in *The pinned bundle*
 rest of the substrate is wanted only once there is a control plane to provision it.
 
 **Step 0 is easy to leave out and it is where several things meet.** A substrate service is a
-container, so Docker must be running before anything else happens — and Docker is a *package*,
-not a container. It is:
+container, so a container runtime must be working before anything else happens — and a runtime
+is a *package*, not a container.
+
+**Which runtime is detected, not chosen**
+([ADR 0060](../../02-DECISIONS/0060-the-host-is-built-per-operating-system.md)): a machine that
+already has one keeps it. On a machine with none, the control plane names the package, because
+what it is called differs per system. It is:
 
 - what the host's capability detection already reports, and the first use of that report by
   something other than a person;