MIN_OTLP_HISTOGRAM_SCALE

Smallest supported OTLP exponential-histogram scale (base 2^32, α ≈ 1 − 4.7·10⁻¹⁰). OTLP itself permits scales down to −10, but below −5 the equivalent DDSketch α rounds to 1.0 in a Double (and at −10 the base 2^1024 overflows entirely), so no valid sketch exists for those scales.