addition to metadata scheme and librarian system prompt, created first overview file, edited PECB transcriptions

metadata/corpus-metadata.md

@@ -16,6 +16,7 @@ The `notetype` field will have one of the following values:
 - `application`: steps to solve a specific, real-world problem. Implementing the standard in real world environments, implementation aids, implementation examples, templates, etc.
 - `reference`: secondary sources of information, like original standard texts, dictionaries, terms and definitions.
 - `publication`: for content created by TSW for publication, e.g. articles, eBooks, social media posts.
+- `overview`: meta-notes created and maintained by the Librarian; describe and index the contents of a vault folder for use by content agents.
 - `other`: for all notes that, by their content, cannot be placed in one of the previous categories.
 - `iso27diyGIS`: notes that belong to the ISO27DIY Guided Implementation System (GIS).
 
@@ -56,6 +57,38 @@ For the possible values of these properties, see [themes-and-attributes-in-iso-2
 - Notes in the `iso27DIY-gis/guide` subfolder ...
 - Notes in the `iso27DIY-gis/reference` subfolder ...
 
+## Properties for Corpus Overview Notes
+
+Overview notes are created and maintained exclusively by the Librarian. They are not content notes and must not be used as source material for publications.
+
+### Folder structure
+
+All overview notes live in `iso27diy-corp/metadata/overviews/`. They are never placed inside the folder they describe.
+
+### Filename convention
+
+`corpus-overview-[foldername].md`, where `foldername` is the name of the vault folder being described, e.g. `corpus-overview-EN.md` for the ISO 27002 EN controls folder.
+
+### Template
+
+```yaml
+---
+title: ""           # human-readable title, e.g. "Corpus Overview: ISO 27002 Controls (EN)"
+notetype: overview
+covers: ""          # vault path of the folder this note describes,
+                    # e.g. "iso27diy-corp/Corpus/Standards/ISO27x/OST/27002/EN"
+last-updated: ""    # ISO 8601 date, e.g. 2026-06-02; update whenever the note is revised
+tags: []
+---
+```
+
+### Rules
+
+- `covers` must be the exact vault path of the folder being described — no trailing slash.
+- `last-updated` must be set every time the overview note is modified.
+- Overview notes do not carry `isotags`, `language`, or `status` — these fields are not applicable.
+- The Librarian updates `last-updated` and the corpus index note (`corpus-index.md`) whenever an overview note is created or revised.
+
 ## Properties for Publications
 
 Publications are found in `iso27diy-corp/Marketing/publications` and are of `notetype` `publication`.