Entity context:
- atlas_id: {atlas_id}
- canonical_label: {canonical_label}
- canonical_description: {canonical_description}
- canonical_type: {canonical_type}
- wikidata_qid: {wikidata_qid}
- wikidata_label: {wikidata_label}
- wikidata_description: {wikidata_description}

Google Trends candidates (JSON):
{candidates_json}

Task:
Pick the best candidate MID for the same real-world entity. If none is reliable, return selected_mid=null.
Respond with strict JSON only.