Fix misleading comments about issue assignment mechanism in reference-impl-sync.yml

Agent-Logs-Url: https://github.com/github/copilot-sdk-java/sessions/70dec3f3-11c0-4254-9792-75f7b1fcf7a2

Co-authored-by: edburns <75821+edburns@users.noreply.github.com>

Author: Copilot

.github/workflows/reference-impl-sync.yml

@@ -129,15 +129,16 @@ jobs:
 
           Follow the [agentic-merge-reference-impl](.github/prompts/agentic-merge-reference-impl.prompt.md) prompt to port these changes to the Java SDK."
 
-          # Create the issue (Copilot coding agent picks it up via the label)
+          # Create the issue with the label; the Copilot coding agent picks up
+          # unassigned issues that carry the configured label.
           ISSUE_URL=$(gh issue create \
             --repo "$REPO" \
             --title "Reference implementation sync: ${COMMIT_COUNT} new commits (${DATE})" \
             --body "$BODY" \
             --label "reference-impl-sync")
 
           echo "issue_url=$ISSUE_URL" >> "$GITHUB_OUTPUT"
-          echo "✅ Issue created and assigned to Copilot coding agent: $ISSUE_URL"
+          echo "✅ Issue created with label for Copilot coding agent: $ISSUE_URL"
 
       - name: Summary
         if: always()