Get Run Host Sources

Deduplicated source destinations for one normalized host within one contributing run.

Lazily backs the Sources matrix's per-host expansion. Destinations are deduplicated by url_digest: identical real URLs collapse into one entry carrying the assistants that cited it and each assistant's COUNT(DISTINCT geo_prompt_result_id) (same grain as the parent matrix cell — the per-run counts here intentionally do NOT reconcile with the period-level parent). Gemini rows are matched by their reconstructed host (from provider_title, via the shared _gemini_reconstructed_host_expr) so a host reached via a real URL and/or a Gemini label resolves in one read; their opaque redirect url is returned for the Open href only, and different redirects stay separate destinations even when they reconstruct to the same host.