chore: Update GitHub Actions workflow for coverage badge handling

.github/workflows/coverage.yml

@@ -5,8 +5,6 @@ on:
     workflows: ["Rust CI"]
     types:
       - completed
-    branches:
-      - main
 
 jobs:
   update-badge:
@@ -18,7 +16,7 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v4
         with:
-          ref: main
+          ref: ${{ github.event.workflow_run.head_branch }}
 
       - name: Download coverage artifacts
         uses: actions/download-artifact@v4
@@ -57,8 +55,19 @@ jobs:
           mkdir -p .github/badges
           echo "{\"schemaVersion\": 1, \"label\": \"coverage\", \"message\": \"${COVERAGE}%\", \"color\": \"$COLOR\"}" > .github/badges/coverage.json
 
-          # Commit and push the badge file
-          git config user.name github-actions
-          git config user.email github-actions@github.com
-          git add .github/badges/coverage.json
-          git diff --staged --quiet || (git commit -m "Update coverage badge [skip ci]" && git push)
+          # Only commit and push badge updates for non-main branches (PRs)
+          # For main branch, the badge will be updated when the PR merges
+          if [ "${{ github.event.workflow_run.head_branch }}" != "main" ]; then
+            git config user.name github-actions
+            git config user.email github-actions@github.com
+            git add .github/badges/coverage.json
+            if ! git diff --staged --quiet; then
+              git commit -m "Update coverage badge [skip ci]"
+              # Push to the PR branch
+              git push origin HEAD:${{ github.event.workflow_run.head_branch }}
+            else
+              echo "✅ No changes to coverage badge"
+            fi
+          else
+            echo "✅ Running on main branch - badge updates happen via PR merges"
+          fi