separate metric comment into its own workflow in order to work with forked PR

.github/workflows/build.yml

@@ -130,12 +130,18 @@ jobs:
             cp metrics.md metrics_compare.md
           fi
 
-      - name: Post Code Metrics as PR Comment
-        if: github.event_name != 'push'
-        uses: marocchino/sticky-pull-request-comment@v2
+      - name: Save PR number
+        if: github.event_name == 'pull_request'
+        run: echo ${{ github.event.number }} > pr_number.txt
+
+      - name: Upload Metrics Comment Artifact
+        if: github.event_name == 'pull_request'
+        uses: actions/upload-artifact@v5
         with:
-          header: code-metrics
-          path: metrics_compare.md
+          name: metrics-comment
+          path: |
+            metrics_compare.md
+            pr_number.txt
 
   # ---------------------------------------
   # Build Make/CMake on Windows/MacOS

.github/workflows/metrics_comment.yml

@@ -0,0 +1,38 @@
+name: Metrics Comment
+
+on:
+  workflow_run:
+    workflows: ["Build"]
+    types:
+      - completed
+
+jobs:
+  post-comment:
+    runs-on: ubuntu-latest
+    if: >
+      github.event.workflow_run.event == 'pull_request' &&
+      github.event.workflow_run.conclusion == 'success'
+    permissions:
+      pull-requests: write
+    steps:
+      - name: Download Artifacts
+        uses: actions/download-artifact@v4
+        with:
+          run-id: ${{ github.event.workflow_run.id }}
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          name: metrics-comment
+
+      - name: Read PR Number
+        id: pr_number
+        run: |
+          if [ -f pr_number.txt ]; then
+            echo "number=$(cat pr_number.txt)" >> $GITHUB_OUTPUT
+          fi
+
+      - name: Post Code Metrics as PR Comment
+        if: steps.pr_number.outputs.number != ''
+        uses: marocchino/sticky-pull-request-comment@v2
+        with:
+          header: code-metrics
+          path: metrics_compare.md
+          number: ${{ steps.pr_number.outputs.number }}