Add Atom HMI site guides and editing playbook

PROJECT.md

@@ -16,8 +16,17 @@ This repository is the shared home for project instructions, confirmed facts, an
 - Preserve project knowledge remotely rather than depending on one computer.
 - Use the connected Atom Git plugin to read and update this repository.
 
-## Details still needed
-- Target AtomHMI URL and environment.
-- Target page and desired changes.
-- Page editor workflow and available backup/export features.
-- Validation and publication requirements for the target environment.
+## Established sites and guides
+
+- Mandel development: https://dev.atomhmi.com/site_mandel/ — MANDEL-BUILD.md and MANDEL-SETTINGS.md.
+- Shop development: https://dev.atomhmi.com/site_atom/ — SHOP-BUILD.md. Do not edit atGVL_alarmManager.
+- ATOMHMI-PLAYBOOK.md: verified native Copy/Paste workflow, tests, and editing pitfalls.
+- SITE-STUDY.md and PAGE-INVENTORY.md: production reference-site study and inventory. Production sites were reference material, not blanket write targets.
+- README.md: project entry point and cloud knowledge base link.
+
+## Cloud references
+
+- Knowledge base: https://chatgpt.com/space/page_59b26c8716dc8191a88caea787825299
+- Atom HMI Editor cloud Space: https://chatgpt.com/space/page_6ad8d4bee7fc8191ba246a2fdf29a5bf
+
+Keep site guides current during project work and reconcile cloud/repository edits before overwriting either. There is no automatic synchronization.