Approve Node 24 workflow baseline

Author: SteveBlackbeard

.chronolith/golden-baseline.json

@@ -1,5 +1,5 @@
 {
-  "change_contract": "docs/change-contracts/2026-08-01-portable-production-boundaries.md",
+  "change_contract": "docs/change-contracts/2026-08-01-actions-node24-runtime.md",
   "files": {
     ".chronolith/feature-registry.json": {
       "bytes": 2395,
@@ -11,7 +11,7 @@
     },
     ".github/workflows/industrial_guardian.yml": {
       "bytes": 4514,
-      "sha256": "602a6a8249066b01efea94e0a7b1290959faacbed66ac0fd4717ededceaf7d28"
+      "sha256": "8008e53ccdad8464273d70b467e36d68f17dd3bceea61cefd36e9787d8ae574d"
     },
     "GOVERNANCE.md": {
       "bytes": 1637,
@@ -58,7 +58,7 @@
       "sha256": "1ea4933b3e1a847ba226e530586f362c75ff92e1df08dd3069d3c6ba23381a71"
     }
   },
-  "generated_at": "2026-08-01T14:59:36+00:00",
+  "generated_at": "2026-08-01T17:36:41+00:00",
   "generated_by": "python scripts/golden_baseline.py refresh",
   "policy": {
     "destructive": false,

docs/change-contracts/2026-08-01-actions-node24-runtime.md

@@ -0,0 +1,70 @@
+# Change Contract: GitHub Actions Node 24 Runtime
+
+## Summary
+
+Move official checkout and Python setup actions to their Node 24 runtime
+majors after GitHub began warning that the previous actions depended on the
+retired Node 20 runner runtime.
+
+## Scope
+
+Expected changes:
+
+- official action major references under `.github/workflows/`;
+- the golden baseline hash for `industrial_guardian.yml`;
+- this reviewed change contract.
+
+Out of scope:
+
+- product Python versions and dependency matrices;
+- Chronolith runtime, cryptography, CLI and package behavior;
+- release publishing or credential policy;
+- ICHIRO and every visual asset.
+
+## Reason
+
+GitHub-hosted runs completed successfully but emitted deprecation warnings for
+`actions/checkout@v4` and `actions/setup-python@v5`. The official succeeding
+majors use Node 24 and support the current hosted runner version.
+
+## Risk
+
+Risk level: low.
+
+Potential failure modes:
+
+- a changed action input contract;
+- runner incompatibility;
+- cache behavior drift;
+- an unreviewed governance baseline change.
+
+## Verification
+
+Required checks:
+
+```text
+python scripts/health_guard.py --strict
+python scripts/golden_baseline.py verify
+python scripts/audit_all.py --install
+```
+
+GitHub must also complete the full Industrial Guardian matrix on the exact PR
+head without Node 20 action-runtime warnings.
+
+## Rollback
+
+Revert the action-major commit and this contract, then refresh the golden
+baseline using an explicit rollback contract. No history rewrite is required.
+
+## Handoff
+
+Record the exact PR head, CI result and any remaining GitHub annotations before
+promotion to `main`.
+
+## Baseline Refresh
+
+This contract approves:
+
+```text
+python scripts/golden_baseline.py refresh --contract docs/change-contracts/2026-08-01-actions-node24-runtime.md
+```