chore(licence): normalise to MPL-2.0 (code) + CC-BY-SA-4.0 (docs)

- LICENSES/ = {MPL-2.0.txt, CC-BY-SA-4.0.txt} (canonical)
- root LICENSE = MPL-2.0 (SPDX header + full body) so GitHub displays MPL-2.0
- SPDX: code -> MPL-2.0, docs (.md/.adoc) -> CC-BY-SA-4.0
- fixed metadata license fields + licence badges; vendored/upstream paths untouched

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

Author: hyperpolymath

.devcontainer/README.adoc

@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: MPL-2.0
+// SPDX-License-Identifier: CC-BY-SA-4.0
 = Dev Container Usage
 :author: Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 

.github/GOVERNANCE.md

@@ -1,4 +1,4 @@
-<!-- SPDX-License-Identifier: MPL-2.0 -->
+<!-- SPDX-License-Identifier: CC-BY-SA-4.0 -->
 
 # Project Governance
 

.github/copilot-instructions.md

@@ -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> -->
 <!-- Authoritative source: docs/AI-CONVENTIONS.md -->
 

.github/pull_request_template.md

@@ -1,4 +1,4 @@
-<!-- SPDX-License-Identifier: MPL-2.0 -->
+<!-- SPDX-License-Identifier: CC-BY-SA-4.0 -->
 ## Summary
 
 <!-- Briefly describe what this PR does and why. Link to related issues with "Closes #N". -->

.github/workflows/codeql.yml

@@ -1,4 +1,4 @@
-# SPDX-License-Identifier: PMPL-1.0
+# SPDX-License-Identifier: MPL-2.0
 name: CodeQL Security Analysis
 
 on:

.github/workflows/governance.yml

@@ -1,4 +1,4 @@
-# SPDX-License-Identifier: PMPL-1.0-or-later
+# SPDX-License-Identifier: MPL-2.0
 name: Governance
 
 on:

.github/workflows/hypatia-scan.yml

@@ -1,4 +1,4 @@
-# SPDX-License-Identifier: PMPL-1.0-or-later
+# SPDX-License-Identifier: MPL-2.0
 name: Hypatia Security Scan
 
 on:

.github/workflows/scorecard.yml

@@ -1,4 +1,4 @@
-# SPDX-License-Identifier: PMPL-1.0-or-later
+# SPDX-License-Identifier: MPL-2.0
 name: OSSF Scorecard
 
 on:

.github/workflows/secret-scanner.yml

@@ -1,4 +1,4 @@
-# SPDX-License-Identifier: PMPL-1.0
+# SPDX-License-Identifier: MPL-2.0
 name: Secret Scanner
 
 on:

.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>
 = Agent Instructions
 :toc: preamble