Bug: texttemplate and hovertemplate show inconsistent values when categoryarray is used in Heatmap

使用 Plotly 6.3.1 通过最小 Python 示例重现该问题，包括反转的 yaxis categoryarray。跟踪类别排序后 heatmap cell values、texttemplate、hovertemplate 和自动文本对比度是如何重新映射的；当显示的值和文本颜色仍与重新定位的单元格保持对应时，即表示完成。

Minimal working example:

import plotly.graph_objects as go

z = [
    [1, None, 30, 50, 1],
    [20, 1, 60, 80, 30],
    [30, 60, 1, -10, 20]
]
x = ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday']
y = ['Morning', 'Afternoon', 'Evening']

fig = go.Figure(
    data=go.Heatmap(
        z=z,
        x=x,
        y=y,
        text=z,
        texttemplate='%{x}<br>%{y}<br>%{text}',
        hovertemplate='%{x}<br>%{y}<br>%{text}<extra></extra>',
    )
)

# Reverse y-axis order
fig.update_layout(yaxis={'categoryarray': y[::-1]})
fig.show()

Expected behavior:

• When the yaxis.categoryarray is reversed, both the heatmap cells and the text (%{text}) / hover labels should display the correctly corresponding values from z.

Actual behavior:

• The axis ordering (x, y) updates correctly.

• The visual placement of heatmap cells updates correctly.

• However, %{text} in hovertemplate still correspond to the original unsorted order of z.

• This leads to mismatched hover and text values after sorting by category.

Example:

After reversing the y axis, the heatmap looks right, but hovering over a cell labeled "Morning / Monday" still shows the value corresponding to "Evening / Monday" from the original order.

Additional note (text color rendering issue)

I also noticed that the text color changes incorrectly after sorting:

In the unsorted heatmap, cells like “Thursday / Evening” show white text on a dark blue background, which is legible and consistent.

After applying the categoryarray sort, the same cell (now visually repositioned) starts showing almost black text on the same dark background, making it nearly invisible.

This suggests that the automatic contrast adjustment for text color (based on cell background) may not update properly after the category sorting.

Version info

plotly.__version__
# 6.3.1