ci: Fix docs release failing on detached HEAD

When manual_release_docs.yaml is invoked with a commit SHA as ref (e.g. from doc_release_post_publish in on_master.yaml or from the stable release pipeline), actions/checkout leaves the repo in a detached HEAD state and the hand-rolled git push fails with "fatal: You are not currently on a branch." Switch to EndBug/add-and-commit with new_branch set to the default branch, and apply the same fix to manual_version_docs.yaml where the same latent bug existed.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: vdusek

.github/workflows/manual_release_docs.yaml

@@ -74,13 +74,13 @@ jobs:
         run: uv run poe update-docs-theme
 
       - name: Commit the updated package.json and lockfile
-        run: |
-          git config user.name 'GitHub Actions'
-          git config user.email 'github-actions[bot]@users.noreply.github.com'
-          git add website/package.json
-          git add website/yarn.lock
-          git diff-index --quiet HEAD || git commit -m 'chore: Automatic docs theme update [skip ci]' || true
-          git push
+        uses: EndBug/add-and-commit@v10
+        with:
+          add: website/package.json website/yarn.lock
+          message: "chore: Automatic docs theme update [skip ci]"
+          default_author: github_actions
+          # Required: checkout may leave a detached HEAD when invoked with a SHA ref.
+          new_branch: ${{ github.event.repository.default_branch }}
 
       - name: Build docs
         run: uv run poe build-docs

.github/workflows/manual_version_docs.yaml

@@ -123,6 +123,8 @@ jobs:
           add: website/versioned_docs website/versioned_sidebars website/versions.json
           message: "docs: Version docs for v${{ steps.snapshot.outputs.version }} [skip ci]"
           default_author: github_actions
+          # Required: checkout may leave a detached HEAD when invoked with a SHA ref.
+          new_branch: ${{ github.event.repository.default_branch }}
 
       - name: Resolve output commitish
         id: resolve_commitish