Chore/update linting tools

[mcocdawc]

Description

Updated and unified the pre-commit hooks in all earthkit packages.
Some of them were failing the test suite just because of the pre-commit hooks.
Fixing this it was a good opportunity to unify settings.

Uses now ruff for formatting (former black), linting, and import sort (former isort)

The following PRs do the same changes in all the earthkit packages:

• Chore/update linting tools #43
• Chore/update linting tools earthkit-data#927
• Chore/update linting tools earthkit-geo#39
• Chore/update linting tools earthkit-hydro#178
• Chore/update linting tools earthkit-meteo#125
• Chore/update linting tools earthkit-plots#176
• Chore/update linting tools earthkit-time#14
• Chore/update linting tools earthkit-transforms#87
• Chore/update linting tools earthkit-workflows#173

Contributor Declaration

By opening this pull request, I affirm the following:

• All authors agree to the Contributor License Agreement.
• The code follows the project's coding standards.
• I have performed self-review and added comments where needed.
• I have added or updated tests to verify that my changes are effective and functional.
• I have run all existing tests and confirmed they pass.

[Copilot]

Pull request overview

This PR updates and unifies linting/formatting tooling across the repository, moving formatting/linting/import sorting to Ruff and aligning pre-commit + CI configuration accordingly.

Changes:

• Update .pre-commit-config.yaml to newer ruff-pre-commit and adjust Ruff hook arguments/exclusions.
• Update pyproject.toml Ruff configuration (line length, lint settings) and normalize optional dependency declarations.
• Apply formatting-only changes across scripts, tests, and documentation notebooks/YAML/workflows to match the new tooling.

Reviewed changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
tools/xclim_wrappers_generator.py	Formatting-only updates to align with new formatter.
tests/unit/utils/test_conversions.py	Import formatting normalized.
tests/unit/conftest.py	Formatting-only updates for dataset fixtures.
src/earthkit/climate/utils/percentile.py	Formatting-only change in sel(...) call.
pyproject.toml	Update Ruff config + rework optional-dependencies declaration.
docs/notebooks/performance_analysis.ipynb	Formatting-only changes inside notebook code cells.
docs/notebooks/climate_indices_analysis.ipynb	Formatting-only import line change in notebook cell.
.readthedocs.yaml	Whitespace cleanup only.
.pre-commit-config.yaml	Ruff hook rev bump + new args/exclude configuration.
.github/workflows/qa.yml	Whitespace cleanup only.
.github/workflows/label-public-pr.yml	Whitespace cleanup only.
.github/workflows/cd-test-pypi.yml	Whitespace cleanup only.
.github/workflows/cd-pypi.yml	Whitespace cleanup only.

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