feat(skills): archify joins the optional-skills catalog as an upstream-maintained stub

tt-a1i/archify (MIT, 57k stars) turns a typed JSON spec into validated,
self-contained interactive HTML diagrams (architecture / workflow /
sequence / dataflow / lifecycle) with a 9-check validate/deliver receipt,
Mermaid import and PNG/SVG/WebM export. The upstream repo already ships a
complete skill directory (archify/), so this follows the impeccable
pattern: a catalog stub whose metadata.hermes.upstream pointer makes
`hermes skills install official/creative/archify` pull the live tree
through OptionalSkillSource._fetch_from_upstream. Nothing executable is
vendored and the copy can never go stale.

Docs: generated page, one catalog row, one sidebar line.

Credit: tt-a1i (upstream author). Supersedes the vendored-references
port in #106442.

optional-skills/creative/archify/SKILL.md

@@ -0,0 +1,52 @@
+---
+name: archify
+description: Validated interactive HTML diagrams, upstream-maintained.
+version: 2.17.0
+author: tt-a1i
+license: MIT
+platforms: [linux, macos, windows]
+metadata:
+  hermes:
+    tags: [diagram, architecture, workflow, sequence, dataflow, state-machine, mermaid, html, svg]
+    category: creative
+    related_skills: [architecture-diagram, excalidraw, concept-diagrams]
+    upstream:
+      repo: tt-a1i/archify
+      path: archify
+---
+
+# Archify (upstream-maintained)
+
+> **Catalog stub.** This entry is maintained upstream at
+> [tt-a1i/archify](https://github.com/tt-a1i/archify): the project ships a
+> self-contained skill directory (`archify/`) with the Node CLI, schemas,
+> renderers, examples and references. `hermes skills install
+> official/creative/archify` pulls the current tree live from that repo
+> (quarantined and scanned like any hub install) — this directory holds only
+> the catalog metadata, so the vendored copy can never go stale.
+
+Archify turns a small typed JSON spec into a self-contained, explorable HTML
+diagram: `architecture`, `workflow`, `sequence`, `dataflow` and `lifecycle`
+(state machine) types, dark/light themes, pan/zoom, search, relationship
+tracing, optional trace motion, and PNG/JPEG/WebP/SVG/WebM export. It accepts
+plain-language requirements or pasted Mermaid (`flowchart`, `sequenceDiagram`,
+`stateDiagram`) and can read repository evidence when the diagram must reflect
+real code. Every candidate goes through a 9-check `validate` / `deliver`
+receipt, so the output is verifiable rather than eyeballed.
+
+## Prerequisites
+
+- Node.js 18+ on `PATH` (`node bin/archify.mjs doctor` confirms the install;
+  no `npm install` is needed inside the skill package).
+- Installs pull ~200 files (~8 MB, mostly upstream tests and examples) from
+  GitHub; the fetch is pinned to one tree SHA, recorded in the bundle metadata.
+- Upstream's "Update awareness" step runs `scripts/check-update.mjs`, which
+  reads a release manifest from GitHub and only prints a notice — it never
+  downloads or installs anything. Skip it if outbound calls are unwanted.
+
+After install, the bundled `architecture-diagram` skill remains the
+zero-dependency fallback (it ports the same Cocoon AI lineage archify grew out
+of); prefer archify when the user wants validated receipts, Mermaid conversion,
+sequence/lifecycle types, or export beyond a single HTML file.
+
+Full documentation: https://github.com/tt-a1i/archify#readme