Add the SQA and QC framework and project instructions

Mount the framework as a submodule at framework/ (v0.4.0), add AGENTS.md and
the installed skill copies for Codex CLI (.agents/skills) and Claude Code
(.claude/skills).

.agents/skills/artifact/templates/DM.md

@@ -0,0 +1,56 @@
+# @TITLE@
+
+## Metadata
+| Key | Value |
+| --- | --- |
+| ID | @ID@ |
+| CrossReference | @CROSSREF@ |
+| Language | @LANGUAGE@ |
+| Domain | @DOMAIN@ |
+
+## Version History
+| Date | Status | Author | Reviewer | Change | Commit |
+| --- | --- | --- | --- | --- | --- |
+| @DATE@ | Proposed | @AUTHOR@ | <reviewer S-ID> | Initial version | pending |
+
+---
+
+## Purpose and Scope
+
+Covers: <use cases>
+
+## Diagram
+
+Concepts, attributes and associations only — no operations.
+
+```plantuml
+@startuml
+class Order {
+  date
+  status
+}
+class Customer {
+  name
+}
+Customer "1" --> "0..*" Order : places
+@enduml
+```
+
+## Concept Table
+
+| Concept | Definition | Attributes | Source (use case / glossary) |
+| --- | --- | --- | --- |
+
+## Association Table
+
+| From | Association (reading direction) | To | Multiplicity |
+| --- | --- | --- | --- |
+
+## Generalizations
+
+| General | Specializations | Is-a justification |
+| --- | --- | --- |
+
+---
+
+@LINKS@