[Feature Request] Add custom label anchor for Sankey graphs

Add the possibility to custom change the anchor of the node text

Current:

After:

Minimum example code:

import dash
from dash import dcc, html, Input, Output
import plotly.graph_objects as go

# Inicializa o app Dash
app = dash.Dash(__name__)
app.title = "Sankey Colorido"

# ----------- Sankey básico -------------
labels = ["A1", "A2", "B1", "B2", "C1", "C2"]
sources = [0, 1, 0, 2, 3, 3]
targets = [2, 3, 3, 4, 4, 5]
values  = [8, 4, 2, 8, 4, 2]

fig = go.Figure(go.Sankey(
    arrangement="snap",
    node=dict(
        pad=15,
        thickness=20,
        line=dict(color="black", width=0.5),
        label=labels,
        color="blue"
    ),
    link=dict(
        source=sources,
        target=targets,
        value=values
    )
))

fig.update_layout(title_text="Basic Sankey Diagram", font_size=10)

# ----------- Layout Dash -------------
app.layout = html.Div([
    dcc.Graph(
        id="sankey-graph",
        figure=fig,
        style={"width":"100%", "height":"100vh"}
    )
])

# ----------- Client-side callback para alinhar labels -------------
# desloca horizontalmente e alinha à direita
app.clientside_callback(
    """
    function(figure) {
        setTimeout(() => {
            const labels = document.querySelectorAll('.sankey .node-label');
            labels.forEach(label => {
                const transform = label.getAttribute('transform');
                const match = /translate\\(([^,]+),([^)]+)\\)/.exec(transform);
                if(match){
                    const y = parseFloat(match[2]);
                    const x = -15; // deslocamento horizontal
                    label.setAttribute('transform', `translate(${x},${y})`);
                    label.setAttribute('text-anchor','end'); // alinhamento à direita
                }
            });
        }, 500); // espera renderização
        return figure;
    }
    """,
    Output('sankey-graph', 'figure'),
    Input('sankey-graph', 'figure')
)

if __name__ == "__main__":
    app.run(debug=True)

The clientside_callback is replaced after user interaction with the graph

issue 中没有指出任何仓库文件或测试。首先跟踪 plotly.js 中 Sankey 节点标签的渲染，并将其与使用 clientside callback 的变通方案进行比较；当受支持的自定义标签锚点在没有该变通方案的情况下仍能在图表交互后保持不变时，即视为完成。