chore(ci): update GitHub Actions and SHA-pin docs.yml

Updates GitHub Actions to their latest releases and switches
.github/workflows/docs.yml from floating major tags to commit-SHA pins, so
every actions/* reference is pinned by SHA with a version comment (matching
the convention used in the other workflows).

- actions/checkout          v6.0.2       -> v7.0.1  (docs.yml was already @v7)
- actions/setup-python       v6 / v6.3.0 -> v7.1.0
- actions/setup-node        v6.4.0       -> v7.1.0
- actions/upload-artifact    v7.0.1      -> v7.0.2
- actions/configure-pages                -> v6.0.0 (SHA-pinned)
- actions/upload-pages-artifact          -> v5.0.0 (SHA-pinned)
- actions/deploy-pages                   -> v5.0.1 (SHA-pinned)

peter-evans/create-pull-request (v8.1.1) and
peter-evans/enable-pull-request-automerge (v3.0.0) are already on their
latest releases and left unchanged.

Safe for our usage: checkout v7 only changes pull_request_target /
workflow_run behavior (unused here); setup-python v7 drops the unused
pip-install input (both usages pass only python-version / cache).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.github/workflows/check-audit.yml

@@ -15,7 +15,7 @@ jobs:
         os: [windows-latest, windows-2022, windows-2025]
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
       - name: Check PowerShell version(PowerShell core)
         run: |
           $PSVersionTable.PSVersion