Publish Elasticsearch migration workshop artifacts

[sishuo-yang]

Summary

• publish the runnable Elasticsearch, Kibana, OpenTelemetry, Terraform, and ClickHouse lab artifacts under workshops/elasticsearch_migration_lab
• include learner-editable migration worksheets, validation scripts, diagrams, and HyperDX reference images
• point instructions and assessment to the hosted WorkshopHouse playbook
• omit the legacy Part 4 question and answer Markdown files now replaced by the interactive 35-question quiz

Verification

• shell syntax checked for every *.sh file
• Python, JSON, NDJSON, and YAML syntax validated
• terraform fmt -check -recursive
• Docker Compose configuration validated for source, OTel Demo, parallel-run, and cutover combinations
• staged diff and credential-pattern scans passed

Companion PRs

• WorkshopHouse playbook: https://github.com/ClickHouse/WorkshopHouse/pull/47
• legacy partners cleanup (merge after both replacements): Remove legacy Elasticsearch migration workshop from partners #93