ADR 0030: the repository structure, and the rule that names them

The tiers were settled and the product was named, but the repositories
themselves existed only in a research sketch. That had already caused two
problems.

ADR 0029 makes the lab phase 0 of the migration and could not say where it
lives, because no record named a repository.

And the sketch contradicted an accepted record: it listed mesh-hq while
ADR 0028 had decided novox/hq and explicitly rejected that name. A design
resting on research is resting on something that can change without a
decision. Corrected in the research too.

The naming rule, which both earlier records implied and neither stated: a
repository belonging to a product carries that product's prefix; a
company-scoped one does not. That is why this repository is hq and the
mesh's are mesh-*.

Seven repositories recorded — host, substrate, control, surfaces, sdk, lab,
and this one. The lab gets its own: it ships to nobody, outlives any single
tier, and drives virtualisation on a workstation, which nothing else does.
Inside the host it would couple development tooling to a shipped
component; inside the control plane the bootstrap scenario would depend on
a tier that does not exist when it is needed.

Tier 4 is deliberately not decided. Whether the catalogue is one
repository, one per domain or one per application stays open from ADR 0015
and is blocked on research 005 — how many repositories hold domains cannot
be answered before knowing what the domains are. mesh-catalog appears in
the sketch and is not decided by this record.

The cost is stated rather than glossed: seven release cadences where there
is one, and cross-repository changes that used to be one commit.

01-RESEARCH/006-mesh-from-scratch/code-skeleton.md

@@ -256,7 +256,7 @@ mesh-surfaces/                 TIER 3
 mesh-catalog/                  TIER 4
     <domain>/<module>/             layout as above
 
-mesh-lab/     mesh-sdk/     mesh-hq/
+mesh-lab/     mesh-sdk/          hq/  (company-scoped — ADR 0028)
 ```
 
 ## What this does not settle

01-RESEARCH/006-mesh-from-scratch/skeleton.md

@@ -84,7 +84,8 @@ mesh-catalog/                  TIER 4 — what the mesh hosts
 
 mesh-lab/                     the whole mesh, disposable, on one machine
 mesh-sdk/                     contracts shared across tiers — types, not behaviour
-mesh-hq/                      this repository
+
+hq/                           company-scoped, not a mesh repository — ADR 0028
 ```
 
 ## The dependency rule