Ship the three C4 examples and model:scaffold --example

- examples/: c4-standard-web-app, c4-e-shop (was online-shop),
  c4-event-based-integration; the same models the extension offers
  under Archify | New Model…
- model-scaffold --example <name> copies one and renames id, name,
  description and the overview title; never overwrites
- tests cover every example and the copy; docs updated

references/authoring.md

@@ -34,7 +34,7 @@ Ids match `^[a-zA-Z][a-zA-Z0-9_-]*$` and are unique in their collection. Relatio
 
 Collections: `components` (required), `connections`, `boundaries`, `cards`, `layout`.
 
-Placement is yours; Archify routes the lines but never moves boxes. Use free positions on this grid, which is what the templates and `examples/online-shop` use:
+Placement is yours; Archify routes the lines but never moves boxes. Use free positions on this grid, which is what the templates and `examples/c4-e-shop` use:
 
 - box `size: [130, 60]` (`[150, 60]` for a system-level box with a longer label)
 - columns at x = 40, 250, 460, 670, 880 (step 210: an 80px clear gap between boxes)

references/folders.md

@@ -73,7 +73,7 @@ How the levels hang together:
 - The container "api" in `containers.archify-registry` points at `0300-components/api.archify`. Click the api, see its components.
 - The same api, drawn in the containers diagram and in several component diagrams, is one entry with one description.
 
-The numbered folders are only for sorting; nothing depends on the names. A team that wants only context and containers has `main.archify`, two folders and two registry files. `task model:scaffold --c4` creates this shape with three levels and empty registries; `examples/online-shop/` in this skill is the filled-in version.
+The numbered folders are only for sorting; nothing depends on the names. A team that wants only context and containers has `main.archify`, two folders and two registry files. `task model:scaffold --c4` creates this shape with three levels and empty registries; `examples/c4-e-shop/` in this skill is the filled-in version (two more examples sit next to it).
 
 Component types that fit C4: people are `external`; the system itself and other systems are `cloud` (own) or `external` (others); containers are `frontend`, `backend`, `database`, `messagebus`, `security`; components inside a container use the same set, wrapped in a `region` boundary named after the container.