ci: fix CI/CD configuration (campaigns C001-C005)

- C001: CodeQL language fixes
- C002: License identifier standardization
- C003: Outdated actions audit
- C004: Pin standards refs to SHA 861b5e9
- C005: Add workflow-level permissions

Author: hyperpolymath

.github/workflows/governance.yml

@@ -30,4 +30,4 @@ permissions:
 
 jobs:
   governance:
-    uses: hyperpolymath/standards/.github/workflows/governance-reusable.yml@main
+    uses: hyperpolymath/standards/.github/workflows/governance-reusable.yml@861b5e911d9e5dcfb3c0ab3dd2a9a3c8fd0a1613

proofs/agda/Ordinal/Buchholz/RankLexJointBplus.agda

@@ -1,4 +1,6 @@
 {-# OPTIONS --safe --without-K #-}
+-- SPDX-License-Identifier: MPL-2.0
+-- SPDX-FileCopyrightText: 2025-2026 Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 
 -- Parallel lex-rank for the joint-bplus bpsi-source-at-equality
 -- sub-case (scaffold, 2026-05-28).