spec: narrow the static-peer federation claim to the shipped inbound evaluation route

[jeremi]

Context

The general architecture spec states at docs/site/src/content/docs/spec/rs-arc-g.mdx:167 (Static-peer delegated evaluation): "A trusted Registry Notary instance can call another trusted Registry Notary instance through POST /federation/v1/evaluations". The shipped product exposes only the inbound evaluation route (crates/registry-notary-server/src/federation/mod.rs); no outbound peer client, JWT-minting caller, or peer-result composition runtime exists in the workspace. Outbound composition is deliberately sequenced as Federation Wave 4 (#36, post-1.0; roadmap tracker #35).

The product-owned docs already state the narrower truth ("Inbound federation ... no outbound Notary client ships", products/notary/docs/notary-capability-matrix.md, since 2026-07-14), but the architecture sentence predates the monorepo (2026-06-22) and survived the later spec-alignment passes untouched. A conformance reviewer or adopter can reasonably conclude two instances can complete an outbound delegated workflow today.

This is a docs-only correction; no code change is warranted.

Scope

• Reword the rs-arc-g.mdx static-peer sentence to describe the shipped capability: Registry Notary accepts inbound static-peer delegated evaluation on POST /federation/v1/evaluations; a separate trusted caller constructs the signed request.
• State that outbound calling and peer-result composition are planned, linking Federation Wave 4: outbound composition #36 (and the Federated Notary roadmap tracker #35 tracker).
• Sweep rs-arc-g.mdx and the other spec pages for any other sentence implying an outbound Notary-to-Notary client ships.
• Note: Federated Notary roadmap tracker #35's embedded checklist links point at stale pre-migration issue numbers; fixing those links can ride along.

Acceptance criteria

• The normative architecture describes federation as inbound-only, matching federation/mod.rs and the capability matrix.
• Outbound composition is explicitly marked planned with a link to Federation Wave 4: outbound composition #36.
• No remaining spec sentence claims an outbound or composed federation workflow.
• Docs site checks pass (npm test and npm run check from docs/site/).