Merge origin/main into add-first-steps-workshops

Integrate the new optional Foundry Agent series into the real-world development CLI workshop paths.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Author: GeekTrainer

AUTHORING.md

@@ -14,7 +14,7 @@ copilot-workshops/
 │   ├── README.md                ← Workshop landing page (also site home via slug: index)
 │   ├── first-steps/             ← Guided introductory workshops
 │   ├── real-world-development/  ← Scenario workshops organized by environment
-│   │   ├── cli/                 ← Copilot CLI lessons
+│   │   ├── cli/                 ← Copilot CLI lessons, including the optional 8-foundry-agent/ series
 │   │   ├── vscode/              ← VS Code lessons
 │   │   ├── cloud/               ← Cloud agent lessons
 │   │   └── app/                 ← GitHub Copilot app lessons
@@ -88,6 +88,12 @@ Every folder's landing page is a `README.md` so it renders directly when someone
 
 When you add a new harness or locale landing, name it `README.md` and set its `slug:` to match the folder path. Localized landings must use the locale-prefixed slug, never the English one.
 
+### Optional multi-module series
+
+An optional series can live in a lesson subfolder, such as `docs/real-world-development/cli/8-foundry-agent/`, with a `README.md` overview and numbered module files. The overview uses `slug: real-world-development/cli/8-foundry-agent` to preserve the series entry URL. The sidebar groups its overview and modules under the optional series title, after the core workshop's review lesson.
+
+Each module has its own objectives, story-focused scenario, numbered instructions, completion checkpoint, and next-module handoff. Shared cleanup instructions live on the overview and are linked from every module so learners can stop at any checkpoint. When moving a lesson into a subfolder, adjust image paths and navigation links for the extra directory level, and keep existing localized entry links aligned; missing module translations use the site's English fallback.
+
 ### Add an image
 
 1. **Drop the file** in `docs/_images/` (or a workshop-scoped `_images/` directory when the image is specific to one workshop). Use lowercase-with-hyphens filenames; prefix with `shared-` if the image is referenced from multiple workshops.