⚙️ ci: Bump GitHub Actions to Node.js 24 Runtimes (#14689)

* ci: bump GitHub Actions to Node.js 24 runtimes

Clear Node 20 deprecation warnings on runners by moving workflow
actions to majors that declare node24 (checkout, cache, setup-node,
artifacts, Docker buildx/build-push/qemu/login, github-script,
setup-go, Azure login/helm, create-pull-request, axe-linter).

* fix: release leader lock via ioredis on Redis Cluster

@keyv/redis EVAL can surface unhandled MOVED redirects on cluster,
so resign() logged failure and left LeadingServerUUID set. Use ioredis
for leader election SET NX / GET / Lua (same pattern as principals and
concurrency locks) so cluster redirects are retried and resignation
clears the lock.

.github/workflows/gitnexus-pr-command.yml

@@ -56,7 +56,7 @@ jobs:
     steps:
       - name: Parse command and resolve PR head ref
         id: parse
-        uses: actions/github-script@v7
+        uses: actions/github-script@v8
         with:
           script: |
             const body = context.payload.comment.body.trim();
@@ -93,7 +93,7 @@ jobs:
             );
 
       - name: Dispatch gitnexus-index workflow
-        uses: actions/github-script@v7
+        uses: actions/github-script@v8
         env:
           EMBEDDINGS: ${{ steps.parse.outputs.embeddings }}
           PR_NUMBER: ${{ steps.parse.outputs.pr_number }}
@@ -130,7 +130,7 @@ jobs:
             });
 
       - name: React to the comment
-        uses: actions/github-script@v7
+        uses: actions/github-script@v8
         with:
           script: |
             await github.rest.reactions.createForIssueComment({