fix(ci): escape special characters in dispatch payload

Author: pescn

.github/workflows/notify-main-repo.yml

@@ -14,4 +14,4 @@ jobs:
           token: ${{ secrets.MAIN_REPO_PAT }}
           repository: EM-GeekLab/NexusGate
           event-type: docs-updated
-          client-payload: '{"message": "Docs updated: ${{ github.event.head_commit.message }}"}'
+          client-payload: '{"sha": "${{ github.sha }}", "ref": "${{ github.ref }}"}'