Add code and asset provenance records

LICENSES/README.md

@@ -0,0 +1,20 @@
+# License and provenance records
+
+No explicit project-wide LICENSE file was identified in either known upstream
+repository during the 2026-08-31 audit:
+
+- https://github.com/shirsig/Mail
+- https://github.com/sica42/TurtleMail
+
+For that reason, this directory does not contain an invented upstream license
+text.
+
+The repository root `LICENSE` is a **mixed-origin scope notice**. It applies
+only to original Dusk-92 material where stated and explicitly does not
+relicense inherited code or assets.
+
+See:
+
+- `../THIRD_PARTY_NOTICES.md`
+- `../Docs/CODE_PROVENANCE.md`
+- `../Docs/ASSET_PROVENANCE.md`