chore(licence): normalise to MPL-2.0 + CC-BY-SA-4.0 (canonical pair) (#658)

Estate licence normalisation. LICENSES/={MPL-2.0,CC-BY-SA-4.0}; root
LICENSE=verbatim MPL-2.0 (GitHub display); code->MPL-2.0,
docs(.md/.adoc)->CC-BY-SA-4.0; vendored untouched. Residual mentions
(mostly legitimate anti-AGPL rules): 159. Manual-review licence PR.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: hyperpolymath

.build/Mustfile

@@ -1,4 +1,4 @@
-# SPDX-License-Identifier: AGPL-3.0-or-later
+# SPDX-License-Identifier: MPL-2.0
 # Mustfile - hyperpolymath mandatory checks
 # See: https://github.com/hyperpolymath/mustfile
 

.build/justfile

@@ -1,4 +1,4 @@
-# SPDX-License-Identifier: MIT OR AGPL-3.0-or-later
+# SPDX-License-Identifier: MPL-2.0 OR AGPL-3.0-or-later
 # SPDX-FileCopyrightText: 2024-2025 hyperpolymath
 # Justfile - hyperpolymath standard task runner for AffineScript
 

.machine_readable/agent_instructions/README.adoc

@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 // Copyright (c) 2026 Jonathan D.A. Jewell (hyperpolymath) <j.d.a.jewell@open.ac.uk>
 = AffineScript Agent Instructions
 :toc: preamble

.machine_readable/svc/k9/README.adoc

@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 = K9 Contractiles
 :toc: left
 :icons: font

AFFIRMATION.adoc

@@ -1,7 +1,7 @@
 ////
   PARKED DRAFT — no SPDX/owner header yet.
   The strict pre-commit hook requires:
-      SPDX-License-Identifier: MPL-2.0
+      SPDX-License-Identifier: CC-BY-SA-4.0
       SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
   Owner adds that header MANUALLY (no automated licence edits), then commits
   SIGNED (-S id_ed25519_signing). Do NOT --no-verify. Until then this file

CHANGELOG.md

@@ -1,5 +1,5 @@
 <!--
-SPDX-License-Identifier: MPL-2.0
+SPDX-License-Identifier: CC-BY-SA-4.0
 SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell (hyperpolymath)
 -->
 

LICENSE

@@ -1,6 +1,3 @@
-SPDX-License-Identifier: MPL-2.0
-SPDX-License-Identifier: CC-BY-SA-4.0
-
 Mozilla Public License Version 2.0
 ==================================
 
@@ -38,7 +35,7 @@ Mozilla Public License Version 2.0
     means any form of the work other than Source Code Form.
 
 1.7. "Larger Work"
-    means a work that combines Covered Software with other material, in
+    means a work that combines Covered Software with other material, in 
     a separate file or files, that is not Covered Software.
 
 1.8. "License"
@@ -360,7 +357,7 @@ Exhibit A - Source Code Form License Notice
 
   This Source Code Form is subject to the terms of the Mozilla Public
   License, v. 2.0. If a copy of the MPL was not distributed with this
-  file, You can obtain one at https://mozilla.org/MPL/2.0/.
+  file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 If it is not possible or desirable to put the notice in a particular
 file, then You may include the notice in a location (such as a LICENSE