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>