…#641)

fixes all the URLs and `main` branch references after move to new org

* updates `pyprojecet.toml` to admit python 3.13 and 3.14
* extends CI to test python 3.14 and 3.13
* python 3.9 end-of-life

This dockerfile introduced by tschm is really no longer needed. We will
work on a modern .devcontainer setup

* introduces limited concurrency for CI jobs, so CI only runs on the
newest commit of a branch and cancels other runs, to save runners
* forces all started CI runs to conclude by adding `fail-fast: False`

Moves packaging completely to `pyproject.toml` from multiple locations:

* `setup.py`
* `requirements.txt`
* `poetry.lock`

No changes to content except where uniformization is requred - e.g.,
`matplotlib` was inconsistently in the core and optional depset.

`pyproject.toml` is the current recommended packaging standard, see
https://packaging.python.org/en/latest/guides/writing-pyproject-toml/

Also:

* removes `poetry` lockfile and related workflows for now.
* updates `checkout` and `setup-python` versions to latest

Moves the CI installs to `uv` - this has no impact on the packaging or
UX, but speeds up the CI VM setup significantly.

Also adds a display step for installed packages for potential
diagnostics.

Also remove a lost workflow in the ISSUE_Template.

typo in CVaR explanation

Towards an updated README file

This PR enables support for plotly 6.

Here we test all notebooks (e.g. we run them from top to bottom) with
nbmake. nbmake is a package produced by our friend Alex Remedios, see
https://github.com/treebeardtech/nbmake. Please note that we had to
update the notebooks following a change in yfinance. We have replaced
"Adj Close" with "Close".

* moves linting to `ruff`
* adds `editorconfig`
* makes tests dependent on passing linting

Also fixes linting in some files (but not all).

merges all PR CI jobs into one workflow, which allows gating and
conditionals.

Also makes all workflows conditional on basic code quality checks to
avoid unnecessary runs.

…#662)

* adds a CI job, `pytest-nosoftdeps`, to test the package without soft
dependencies.
* isolates soft dependency `matplotlib` in tests and the plotting module
* isolates the `ecos` dependency almost entirely. There is one default
that remains, which is deprecated and scheduled for removal in 1.7.0.
* adds `scikit-base` soft dependency (without further dependencies) to
manage soft dependencies

This is also useful to check whether soft dependencies are properly
isolated.

restores the `requirements.txt` for downwards compatibility

`scikit-learn` is a soft dependency - this PR fully isolates
`scikit-learn` with dependency checks.

It is not removed from the core dependency set, even though the
dependency is entirely localized in the `CovarianceShrinkage` object,
since it seems to be called frequently from the rest of the code base.

…ake8"

This reverts commit 6c9a1d6, reversing
changes made to e5ac43d.