docs: the four claims the capability matrix did not reach, and the gate caught the author of this commit (#591)

[stephrobert]

Four sentences the capability matrix of #592 does not yet reach, each measured in
the files before being touched. Part of #591, and deliberately not its
P1s.

The Quick Start's four commands install feint and not the engine they run

examples/quickstart/scaleway/feint.yaml declares iac.engine: terraform and
its main.tf requires >= 1.7.0. The block installs feint, clones, changes
directory and runs — so a reader on a bare machine cannot reach the
Apply complete! the block prints underneath. That is #593's own complaint,
one level out: a Quick Start displaying an output its own commands cannot
produce.

It now names Git and the engine above the commands:

> You need **Git** and **Terraform >= 1.7.0**. feint itself has no runtime
> dependency: it is the stack that asks for the engine.

The version is read, never typed — from the declaration's engine: and the
configuration's required_version. A number written beside a file that owns it
goes stale in silence, which is precisely what happened to the resource count
this same block had to stop inventing. When either is missing the line is
omitted rather than guessed: a prerequisite naming a version nobody declared is
worse than none, because a reader installs it and still fails.

"No credentials" was not what is true

The quickstart carries a fake access key and secret key on purpose — the
official client requires syntactically valid values, and they are deliberately
public. It says "no cloud credentials" now, in both languages.

Two sentences asserted an implicit matrix

docs/install.md said "scw, octl, exo and Terraform drive it" without
saying which packs an engine drives.

And the safety block said "scw, octl, exo, Terraform and OpenTofu run
against the emulator in CI".

The part worth recording: the gate caught the author of this commit

The first rewrite of that safety sentence named three CLIs and two providers
in one unit. docs:check refused it four times over:

README.md, in the generated `safety` block, puts `exo` and Outscale together
  and capabilityMatrix carries no row for that pair
… `exo` and Scaleway …
… `octl` and Scaleway …
… `scw` and Outscale …

The claim reader treats a unit naming several packs and several clients as
asserting every pair — which is exactly the argument #592's own report made
two hours earlier, and which the author of this commit then walked into.

The sentence now names no pair at all: each pack's own official CLI, and an
infrastructure engine wherever a pack admits one.

A gate shipped this afternoon refusing this afternoon's next commit is the best
evidence it works that this branch could offer.

Outside every gate: the repository description

before  Run Terraform, OpenTofu and the official Scaleway, Outscale and Exoscale
        CLIs locally — no cloud account, no credentials, nothing billed.
after   A local emulator of the Scaleway, Outscale and Exoscale APIs. Their own
        official CLIs drive it end to end, Terraform and OpenTofu drive two of
        the three — no cloud account, no cloud credentials, nothing billed.

Corrected by hand, because it is outside everything feint docs --check can
reach. Worth knowing rather than assuming a gate covers it.

Also here, and unrelated

maquettes-site/ sat untracked in the working tree. Untracked is not pushed
— git ships commits and it was in none, verified — but untracked is one
git add -A away from being staged, and the ignore line that had been there was
already lost once to a pre-commit stash and restore. It is ignored now.

Gates

mise run prepush 0 · mise run docs:check 0 — and 2 on the first rewrite,
which is the finding above.

What is deliberately not here

The P1s of #591 — a docs/ index, the user-versus-fidelity CLI split, a short
limits summary above the 3489-line record, confidence.md as an entry point —
are structure, not fidelity, and they deserve their own lot. docs/limits.md
is untouched because another lot is measuring #587 and may write there.