[Elastic Workflows] add elastic_workflows Fleet content package

[rosomri]

Introduce a content package with a Workflows execution overview dashboard for existing .workflows-executions data (Kibana 9.3+). Includes _dev scripts to regenerate the dashboard JSON.

Closes elastic/security-team#15773

WHAT: Adds the elastic_workflows Fleet content package: one managed dashboard (elastic_workflows-8de4b190-…) built with Lens against .workflows-executions, filtering out test runs. Dev-only assets live under _dev/scripts and _dev/shared to regenerate the dashboard JSON; the saved object id matches the dashboard filename per elastic-package rules.

WH: Workflows execution data already exists in Elasticsearch; this package ships ready-made analytics in Integrations without Agent inputs or data streams, aligned with Kibana 9.3+ where Workflows is available.

Checklist

• I have reviewed tips for building integrations and this pull request is aligned with them.
• I have verified that all data streams collect metrics or logs. (N/A — content-only package; no data streams.)
• I have added an entry to my package's changelog.yml file.
• I have verified that Kibana version constraints are current according to guidelines.
• I have verified that any added dashboard complies with Kibana's Dashboard good practices

Author's Checklist

• Owner team (elastic/platform-deployment-management) is aware / has reviewed.

How to test this PR locally

cd packages/elastic_workflows
elastic-package check
elastic-package build
# Optional: install build/packages/elastic_workflows-0.1.0.zip via Fleet upload API against Kibana 9.3+

Screenshots

Note: The icon and integration page should be revisited.

[github-actions]

✅ Vale Linting Results

No issues found on modified lines!

---

The Vale linter checks documentation changes against the Elastic Docs style guide.

To use Vale locally or report issues, refer to Elastic style guide for Vale.

[elasticmachine]

💚 Build Succeeded

• Buildkite Build
• Commit: 67628cf