We need to output JSON with fields: seo_title, summary, key_entities (companies, people, locations), expert_faq (question, answer), internal_link_anchor, primary_keyword, secondary_keywords, content_type.

We need summary 180-250 words, split into 3-4 paragraphs each 45-65 words. Must bold selective key details using **. Must avoid banned words.

We have source: "Lamine Yamal has said he'd welcome Atlético Madrid forward Julián Álvarez 'with open arms' at Barcelona next season."

Thus we know: Lamine Yamal (player, Barcelona), Julián Álvarez (forward, Atlético Madrid), Barcelona, Atlético Madrid, next season.

We need to elaborate but cannot invent facts not implied. We can discuss context: Yamal is a Barcelona youngster, Álvarez is a forward, potential transfer rumors, implications for Barcelona's attack, Atlético's situation, etc. But must not invent specifics like stats, contract values, etc unless implied. We can infer that Yamal is a Barcelona player, Álvarez is Atlético forward, and that Yamal's comment suggests openness to signing him. We can discuss that Barcelona may be looking to bolster attack, Atlético may consider selling, etc. But we must not invent specifics like "Barcelona are seeking a striker" unless implied? The source only says Yamal would welcome Álvarez at Barcelona next season. It implies that Álvarez could be a transfer target for Barcelona, and that Yamal is a Barcelona player. We can elaborate on what that might mean: potential impact on Barcelona's forward line, competition for places, etc. But we must be careful not to invent stats like "Álvarez scored X goals last season". That would be invented. We can only use info from source: names, clubs, that Yamal said he'd welcome Álvarez with open arms at Barcelona next season. We can infer that it's a comment about a possible transfer, but we cannot assert that a transfer is likely or that Barcelona are interested; we can say Yamal's comment suggests he would be happy to play alongside him. Tha