List evidence items, including contradictions and exclusions. Filters are honest (1.30.0): `q` is full text over subject AND content, `subject` matches by CONTAINS (case-insensitive), `subject_exact` is the old exact equality.

Filters are strict and always applied; the response echoes them in filtered_by, including tsquery_used and subject_match. q uses websearch_to_tsquery with the 'simple' configuration, the same matching as GET /search?type=evidence. Every item carries its provenance (source.session_id, source.session_title, source.artifact_id, source.artifact_title) and its epistemic relations (contradicts, contradicted_by, supersedes, superseded_by), so a claim and its contradiction each point at the other. A sessionId belonging to another workspace, or one that does not exist, returns 404 session_not_found — never another session's evidence. A query parameter this endpoint does not read is refused with 400 unknown_parameter.