Generate Archify cards from registry descriptions for model diagrams

An architecture diagram inside a model that defines no cards gets one card
per drawn shared element with a description, as the extension does. Test
covers the resolved JSON; formats.md and SKILL.md describe the rule.

SKILL.md

@@ -175,6 +175,7 @@ Diagrams next to `main.archify` are listed first, ungrouped; deeper ones by fold
 - **Links are relative to the model root**, never to the file, and must end in `.archify` and exist. `..` is refused.
 - **A second `main.archify` deeper down** is reported, not nested. One model per tree.
 - **Diagram kinds other than architecture** take `ref` too (workflow and dataflow `nodes`, sequence `participants`, lifecycle `states`), but the registry `type` must fit that kind: lifecycle states use their own type enum, and sequence participants have no `tag`.
+- **Cards come from the registry.** A model diagram without `cards:` gets one card per drawn shared element that has a description. To show something else below the diagram, write `cards:` yourself; to show nothing, write `cards: []`.
 - **No em dashes or smart quotes in ids**; ids match `^[a-zA-Z][a-zA-Z0-9_-]*$`.
 
 ## References

references/formats.md

@@ -100,3 +100,7 @@ For each diagram file under the root (and a single file outside a model):
 5. Hand the result to `archify validate <kind> <json> --json` (or `render`).
 
 `task model:resolve -- --file=… --out=x.json` writes step 4's result.
+
+## Cards under a model diagram
+
+Archify shows `cards` (a coloured dot, a title, a few lines) below a diagram. An architecture diagram inside a model that draws shared elements and defines no `cards` of its own gets one card per drawn element that has a `description` in the registry, in drawing order, with the dot colour of the element's type (frontend cyan, backend emerald, database violet, cloud amber, security rose, messagebus orange, external slate). `model:resolve` and the extension both add them; write your own `cards:` in the diagram to replace them.

scripts/src/services/model.mjs

@@ -28,6 +28,18 @@ const COPY = {
 };
 // What a diagram may override on a shared element. Everything else in COPY is fixed.
 export const OVERRIDE = ['label', 'sublabel', 'tag'];
+// Archify card dot colour per component type (the colour Archify gives the node).
+const DOT_BY_TYPE = { frontend: 'cyan', backend: 'emerald', database: 'violet', cloud: 'amber', security: 'rose', messagebus: 'orange', external: 'slate' };
+export const dotForType = (type) => DOT_BY_TYPE[type ?? ''] ?? 'slate';
+
+// Archify info cards for shared elements: one per element with a description,
+// titled by its label. An architecture diagram without cards of its own gets
+// these for the elements it draws, as the extension does.
+export function cardsFromElements(elements) {
+  return elements
+    .filter((element) => typeof element.description === 'string' && element.description.trim())
+    .map((element) => ({ dot: dotForType(element.type), title: element.label ?? element.id, items: [element.description.trim()] }));
+}
 // Registry-only fields, never sent to Archify.
 const REGISTRY_ONLY = ['description', 'diagram'];
 const SKIP_DIRS = new Set(['node_modules', '.git']);
@@ -241,6 +253,11 @@ export function resolveDiagram(file, { root, elements } = {}) {
     }
     return merged;
   });
+  if (type === 'architecture' && diagram.cards === undefined && refs.length) {
+    const drawn = [...new Set(refs)].map((ref) => elements?.[ref]).filter(Boolean);
+    const cards = cardsFromElements(drawn);
+    if (cards.length) diagram.cards = cards;
+  }
   result.resolved = diagram;
   return result;
 }

scripts/src/test/run.mjs

@@ -80,7 +80,10 @@ try {
     assert(json.model === undefined, 'model block leaked into the resolved JSON');
     const api = json.components.find((c) => c.id === 'api');
     assert(api && api.type === 'backend' && api.brand === 'node-js' && api.description === undefined && api.diagram === undefined, 'api was not resolved from the registry');
-    notes.push(`${json.components.length} components, refs expanded`);
+    const cards = json.cards ?? [];
+    assert(cards.length === 7 && cards.every((c) => c.dot && c.title && c.items.length === 1), `expected 7 generated cards, got ${JSON.stringify(cards).slice(0, 200)}`);
+    assert(cards.find((c) => c.title === 'API')?.dot === 'emerald', 'API card has the backend colour');
+    notes.push(`${json.components.length} components, refs expanded, ${cards.length} cards from the registry`);
   });
 
   check('model-resolve prints the JSON inline without --out', ['--action', 'model-resolve', '--file', path.join(example, 'main.archify')], (r) => {