ci: set git committer identity before merging the target branch

.github/workflows/ci-cmake_tests.yml

@@ -30,9 +30,13 @@ jobs:
       # When re-running a PR job, GitHub Actions uses the merge commit created at
       # the time of the original run, not a fresh merge with the latest target branch.
       # This step ensures we always test against the most recent target branch.
+      # A committer identity is required because a non-fast-forward merge creates
+      # a merge commit.
       - name: Merge with latest target branch (pull_request only)
         if: github.event_name == 'pull_request'
         run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "github-actions[bot]@users.noreply.github.com"
           git fetch origin ${{ github.event.pull_request.base.ref }}
           git merge --no-edit origin/${{ github.event.pull_request.base.ref }}
           # Refresh submodules in case the merge moved any gitlinks (e.g. cmake_modules/morse_cmake).

.github/workflows/ci-downstream-find-package.yml

@@ -61,9 +61,13 @@ jobs:
 
       # Match ci-cmake_tests.yml: re-runs of a PR job use the original merge
       # commit, so merge the latest target branch to test against current tip.
+      # A committer identity is required because a non-fast-forward merge creates
+      # a merge commit.
       - name: Merge with latest target branch (pull_request only)
         if: github.event_name == 'pull_request'
         run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "github-actions[bot]@users.noreply.github.com"
           git fetch origin ${{ github.event.pull_request.base.ref }}
           git merge --no-edit origin/${{ github.event.pull_request.base.ref }}
           # Refresh submodules in case the merge moved any gitlinks.

.github/workflows/clang-format-check.yml

@@ -14,9 +14,13 @@ jobs:
     # When re-running a PR job, GitHub Actions uses the merge commit created at
     # the time of the original run, not a fresh merge with the latest target branch.
     # This step ensures we always test against the most recent target branch.
+    # A committer identity is required because a non-fast-forward merge creates
+    # a merge commit.
     - name: Merge with latest target branch (pull_request only)
       if: github.event_name == 'pull_request'
       run: |
+        git config user.name "github-actions[bot]"
+        git config user.email "github-actions[bot]@users.noreply.github.com"
         git fetch origin ${{ github.event.pull_request.base.ref }}
         git merge --no-edit origin/${{ github.event.pull_request.base.ref }}
 

.github/workflows/conda_build.yml

@@ -30,9 +30,13 @@ jobs:
     # When re-running a PR job, GitHub Actions uses the merge commit created at
     # the time of the original run, not a fresh merge with the latest target branch.
     # This step ensures we always test against the most recent target branch.
+    # A committer identity is required because a non-fast-forward merge creates
+    # a merge commit.
     - name: Merge with latest target branch (pull_request only)
       if: github.event_name == 'pull_request'
       run: |
+        git config user.name "github-actions[bot]"
+        git config user.email "github-actions[bot]@users.noreply.github.com"
         git fetch origin ${{ github.event.pull_request.base.ref }}
         git merge --no-edit origin/${{ github.event.pull_request.base.ref }}
         # Refresh submodules in case the merge moved any gitlinks (e.g. cmake_modules/morse_cmake).