fix: keep Y-axis ticks evenly spaced when Recharts thins them for overlap

.changeset/y-axis-even-tick-spacing.md

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+---
+'@hyperdx/app': patch
+---
+
+fix: keep Y-axis ticks evenly spaced and cleanly rounded
+
+A chart's Y-axis could render unevenly spaced or fractional ticks (e.g. `0, 300, 1k` instead of `0, 250, 500, 750, 1k`), or even show two ticks with the identical label. Ticks now round to clean, evenly-spaced, always-distinct values instead.