Add prefix query parameter to /admin/opensearch/indices endpoint so the UI can fetch execution and log indices separately. OpenSearch admin page now shows two card sections: Execution Indices and Log Indices, each with doc count and size summary. Page restyled with CSS module replacing inline styles. Delete endpoint also allows log index deletion. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>