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/QC.md

@@ -0,0 +1,42 @@
+# @TITLE@
+
+## Metadata
+| Key | Value |
+| --- | --- |
+| ID | @ID@ |
+| CrossReference | @CROSSREF@ |
+
+## Version History
+| Date | Status | Author | Reviewer | Change | Commit |
+| --- | --- | --- | --- | --- | --- |
+| @DATE@ | Proposed | @AUTHOR@ | <reviewer S-ID> | Initial version | pending |
+
+Allowed Status values: `Proposed`, `Accepted`, `Rejected`, `Deprecated`. The latest reviewed row is `Accepted`; the row before it is `Deprecated`.
+
+---
+
+## Purpose
+
+<Why this artifact type matters and what decision it supports.>
+
+## Quality Criteria Checklist
+
+Level: **Mandatory** criteria are the baseline every instance must meet; **Optional** criteria are advanced and may be deferred.
+
+| # | Criterion | Level | ISO/IEC 25010 Characteristic(s) | Notes |
+| --- | --- | --- | --- | --- |
+| 1 | <criterion> | Mandatory | <characteristic(s)> | |
+
+## Common Defects
+
+- <anti-pattern 1>
+- <anti-pattern 2>
+
+## Traceability Rule
+
+- Backward: <what this artifact must link to as input> ([QC-<BACKWARD-SHORT-NAME>-<NNN>])
+- Forward: <what this artifact must feed into as output> ([QC-<FORWARD-SHORT-NAME>-<NNN>])
+
+---
+
+@LINKS@