compat: cuDF 26.04

[hoxbro]

Description

Bump cuDF version in pixi lock

How Has This Been Tested?

Locally

Checklist

• Tests added and are passing

[codspeed-hq]

Merging this PR will degrade performance by 54.97%

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

❌ 5 regressed benchmarks
✅ 47 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
❌	Simulation	test_layout[forceatlas2_layout]	56.1 ms	124.5 ms	-54.97%
❌	Simulation	test_quadmesh_raster[256]	14.8 ms	18.1 ms	-18%
❌	Simulation	test_dask_raster[256]	141.9 ms	164.9 ms	-13.94%
❌	Simulation	test_bundle[forceatlas2_layout-connect_edges]	8.1 ms	9.4 ms	-13.24%
❌	Simulation	test_quadmesh_curvilinear[512]	80.7 ms	89.8 ms	-10.14%

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_{Comparing compat_cudf_26_04 (7a140eb) with main (0c4e970)}