Expand README for src/webhooks (#58905)

Co-authored-by: Robert Sese <734194+rsese@users.noreply.github.com>

Author: heiskr

src/webhooks/README.md

@@ -57,3 +57,37 @@ Slack: `#docs-engineering`
 Repo: `github/docs-engineering`
 
 If you have a question about the webhooks pipeline, you can ask in the `#docs-engineering` Slack channel. If you notice a problem with the webhooks pipeline, you can open an issue in the `github/docs-engineering` repository.
+
+## Ownership & Escalation
+
+### Ownership
+- **Team**: Docs Engineering
+- **Source data**: API Platform (github/rest-api-description)
+
+### Escalation path
+1. **Pipeline failures** → #docs-engineering Slack
+2. **OpenAPI schema issues** → #api-platform Slack
+3. **Production incidents** → #docs-engineering
+
+### On-call procedures
+If the webhooks pipeline fails:
+1. Check workflow logs in `.github/workflows/sync-openapi.yml`
+2. Verify access to `github/rest-api-description` repo
+3. Check for OpenAPI schema validation errors
+4. Review changes in generated data files
+5. Check `config.json` SHA tracking
+6. Escalate to API Platform team if schema issue
+
+### Monitoring
+- Pipeline runs automatically on daily schedule (shared with REST/GitHub Apps)
+- PRs created with `github-openapi-bot` label
+- SHA tracking in `config.json` for version history
+- Failures visible in GitHub Actions
+
+This pipeline is in maintenance mode. We will continue to support ongoing improvements incoming from the platform but we are not expecting new functionality moving forward.
+
+### Known limitations
+- **Shared pipeline** - Cannot run webhooks independently of REST/GitHub Apps
+- **Single page** - All events on one page (may impact performance)
+- **Introduction placement** - Manual content must be at start of file
+- **Payload complexity** - Some payloads are very large and complex