brushXFilter was hiding and overwriting the Y axis scale domain (and vice versa for brushYFilter), causing Y axis ticks to change after an X-only brush filter operation.

Root causes

• BrushFilter defaulted hideY: true for all subclasses, including BrushXFilter — causing the Y axis to flash hide/show during re-render, appearing as a tick change
• BrushFilter unconditionally set both scale.x.domain and scale.y.domain with nice: false, even when only one axis was being filtered — potentially producing different tick positions than the original scale

Changes

• brushFilter.ts: Add filterX and filterY boolean params to BrushFilter. Scale domains are only updated for axes where the corresponding flag is true:

  scale: {
    ...(filterX && { x: { domain: domainX, nice: false } }),
    ...(filterY && { y: { domain: domainY, nice: false } }),
  }

• brushXFilter.ts: Pass hideY: false, filterY: false — Y axis is unaffected when filtering X
• brushYFilter.ts: Pass hideX: false, filterX: false — X axis is unaffected when filtering Y
• interaction.spec.ts: Add unit tests asserting Y domain is unchanged after brushXFilter and X domain is unchanged after brushYFilter

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