Phân tích sâu chuyên nghiệp về tennis: Dữ liệu đầu vào rỗng

core_answer: No tennis analysis possible: Stage-1 input empty, zero players, matches or events extracted.
key_facts: Stage-1 information points: 0 items; Entities involved: none; All dimensions rated N/A; No player names or tournament data available; Analysis cannot proceed without re-running Stage-1
source_attribution: Stage-2 Deep Professional Analysis Report (empty payload)
related_qa: What caused the empty input? Stage-1 extraction failed to process the article text.; Can analysis resume? Yes, after re-running Stage-1 with valid content.