feat: Add dendrogram

[hoxbro]

resolves #6501

TODO:

• Adjoint plot support responsive (will be done with: Improve responsive in adjoint layout for Bokeh backend #6527)
• Adjoint plot weird height issue (problem: shared kdims in height axis: hv.Curve([]) << hv.Path([(0, 0), (1, 1)]) << hv.Path([(0, 0), (200, 200)]))
• Add tests
• Add examples
• Don;t need to use Dendrogram(zip(...)) for creating the data

Screencast.From.2025-02-24.17-41-32.mp4

Details

import random

import pandas as pd
import panel as pn

import holoviews as hv

hv.extension("bokeh")
hv.opts.defaults(
    hv.opts.HeatMap(width=700, height=400, border=0, tools=["hover"]),
)
random.seed(1)


df = pd.DataFrame(
    [(i, chr(65 + j), random.random()) for j in range(10) for i in range(5)],
    columns=["z", "x", "y"]
)
dataset = hv.Dataset(df, vdims="y")  # TODO: Should not be needed

for adjoint_dims in (["x", "z"], ["x"], ["z"]):
    dendro = hv.operation.dendrogram(dataset, adjoint_dims=adjoint_dims, main_dim="y")
    pn.panel(dendro).servable()

[codecov]

Codecov Report

Attention: Patch coverage is 31.16883% with 53 lines in your changes missing coverage. Please review.

Project coverage is 88.73%. Comparing base (2465ad1) to head (206ab68).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
holoviews/operation/element.py	21.62%	29 Missing ⚠️
holoviews/plotting/bokeh/path.py	14.28%	24 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6511      +/-   ##
==========================================
- Coverage   88.79%   88.73%   -0.07%     
==========================================
  Files         323      323              
  Lines       68949    69023      +74     
==========================================
+ Hits        61225    61246      +21     
- Misses       7724     7777      +53     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[droumis]

@hoxbro , is this ready for review?