feat(#2182): add EoS Registry catalog (eos.json + generated eos-registry.md)

Instantiates the second discoverability catalog from issue #2182 on top of the
shared registry foundation shipped in PR #2188: an empty eos.json source and the
generated eos-registry.md (EoS entries declare the six Host-Integration interface
points, eight negotiated axes, and protocol version per ADR-1239). The validation,
generation, and rendering machinery + README schema + glossary term already landed
and are tested in PR #2188; this PR adds the EoS registry data + catalog page.

Closes #2182

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.changeset/merry-tigers-parade.md

@@ -0,0 +1,5 @@
+---
+type: Added
+pr: 0
+---
+**Discover third-party GSD Embeddable Orchestration System (EoS) integrations in a new EoS Registry.** — A non-endorsing discoverability catalog where host-integration authors register via a documentation PR; each entry declares its Host-Integration interface points, negotiated axes, and protocol version, with a live release badge and a per-entry GitHub Discussion for ranking and comments. (#0)

docs/registries/eos-registry.md

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+<!-- GENERATED by scripts/gen-registry.cjs from docs/registries/eos.json — do not edit by hand; run `npm run gen:registry` -->
+
+# GSD EoS Registry
+
+> **Not an endorsement.** Inclusion means only that a maintainer merged a PR linking the author's repository — GSD has not reviewed, tested, or verified any listing. See the [registry README](./README.md).
+
+_To add your integration, see the [registry README](./README.md)._
+
+_No entries yet — be the first: see [README](./README.md)._

docs/registries/eos.json

@@ -0,0 +1 @@
+[]