sagemathgh-40124: Update Meson and Conda install instructions 
    
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Make the Meson build instructions independent from the Conda and sage-
the-distro instructions (previously it was linking to the relevant
section for the basic setup).
Also includes now how to use `uv` to setup a python env.

The conda instructions have been also updated, based on the work in
sagemath#39515.


### 📝 Checklist

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- [ ] The title is concise and informative.
- [ ] The description explains in detail what this PR is about.
- [ ] I have linked a relevant issue or discussion.
- [ ] I have created tests covering the changes.
- [ ] I have updated the documentation and checked the documentation
preview.

### ⌛ Dependencies

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URL: sagemath#40124
Reported by: Tobias Diez
Reviewer(s):

Author: Release Manager

.devcontainer/onCreate-meson.sh

@@ -20,10 +20,11 @@ uv venv
 uv pip install \
     meson-python \
     "cypari2 >=2.2.1" \
-    "cysignals >=1.11.2, != 1.12.0" \
+    "cython >=3.0, != 3.0.3, != 3.1.0" \
     "cython >=3.0, != 3.0.3" \
     "gmpy2 ~=2.1.b999" \
     memory_allocator \
     "numpy >=1.25" \
-    jinja2
-uv sync --frozen --inexact --no-build-isolation-package=sagemath
+    jinja2 \
+    setuptool
+uv sync --frozen --inexact --no-build-isolation

.github/workflows/ci.yml

@@ -62,16 +62,16 @@ jobs:
         run: |
           # Install build dependencies manually as workaround for https://github.com/astral-sh/uv/issues/1516
           uv pip install \
-            meson-python \
-            "cypari2 >=2.2.1" \
-            "cysignals >=1.11.2, != 1.12.0" \
-            "cython >=3.0, != 3.0.3" \
-            "gmpy2 ~=2.1.b999" \
-            memory_allocator \
-            "numpy >=1.25" \
-            jinja2
-
-          uv sync --frozen --inexact --no-build-isolation-package=sagemath
+              meson-python \
+              "cypari2 >=2.2.1" \
+              "cython >=3.0, != 3.0.3, != 3.1.0" \
+              "cython >=3.0, != 3.0.3" \
+              "gmpy2 ~=2.1.b999" \
+              memory_allocator \
+              "numpy >=1.25" \
+              jinja2 \
+              setuptool
+          uv sync --frozen --inexact --no-build-isolation
 
       - name: Test
         run: |

.vscode/settings.json

@@ -70,6 +70,8 @@
         "mathrm",
         "Michal",
         "micjung",
+        "Miniconda",
+        "Miniforge",
         "Minkowski",
         "Möbius",
         "mpfr",

src/doc/en/installation/conda.rst

@@ -9,19 +9,17 @@ SageMath can be installed on Linux and macOS via Conda from the
 Both the ``x86_64`` (Intel) architecture and the ``arm64``/``aarch64``
 architectures (including Apple Silicon, M1, M2, M3, M4) are supported.
 
-You will need a working Conda installation: either Miniforge (or Mambaforge),
-Miniconda or Anaconda. If you don't have one yet, we recommend installing
-`Miniforge <https://github.com/conda-forge/miniforge>`_ as
-follows. In a terminal,
+You will need a working Conda installation: either Miniforge, Miniconda or
+Anaconda. If you don't have one yet, we recommend installing `Miniforge
+<https://github.com/conda-forge/miniforge>`_ as follows. In a terminal,
 
 .. code-block:: shell
 
-   $ curl -L -O "https://github.com/conda-forge/miniforge/releases/latest/download/Miniforge3-$(uname)-$(uname -m).sh"
-   $ bash Miniforge3-$(uname)-$(uname -m).sh
+    $ curl -L -O "https://github.com/conda-forge/miniforge/releases/latest/download/Miniforge3-$(uname)-$(uname -m).sh"
+    $ bash Miniforge3-$(uname)-$(uname -m).sh
 
-* Miniforge (and Mambaforge) use conda-forge as the default channel.
-
-* If you are using Miniconda or Anaconda, set it up to use conda-forge:
+* Miniforge uses conda-forge as the default channel. However, if you are using
+  Miniconda or Anaconda, set it up to use conda-forge:
 
   * Add the conda-forge channel: ``conda config --add channels conda-forge``
 
@@ -42,15 +40,13 @@ Create a new conda environment containing SageMath, either with ``mamba`` or ``c
 
   .. code-block:: shell
 
-      $ mamba create -n sage sage python=X
+      $ mamba create -n sage sage
 
 .. tab:: conda
 
   .. code-block:: shell
 
-      $ conda create -n sage sage python=X
-
-where ``X`` is version of Python, e.g. ``3.12``.
+      $ conda create -n sage sage
 
 To use Sage from there,
 
@@ -60,95 +56,3 @@ To use Sage from there,
 If there are any installation failures, please report them to
 the conda-forge maintainers by opening a `GitHub Issue for
 conda-forge/sage-feedstock <https://github.com/conda-forge/sage-feedstock/issues>`_.
-
-.. _sec-installation-conda-develop:
-
-Using conda to provide all dependencies for the Sage library
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-You can build and install the Sage library from source, using conda to
-provide all of its dependencies. This bypasses most of the build
-system of the Sage distribution and is the fastest way to set up an
-environment for Sage development.
-
-Here we assume that you are using a git checkout.
-
-- Optionally, set the build parallelism for the Sage library. Use
-  whatever the meaningful value for your machine is - no more than
-  the number of cores::
-
-    $ export SAGE_NUM_THREADS=24
-
-- Create and activate a new conda environment with the dependencies of Sage
-  and a few additional developer tools:
-
-  .. tab:: mamba
-
-    .. code-block:: shell
-
-        $ mamba env create --file environment-3.12-linux.yml --name sage-dev
-        $ conda activate sage-dev
-
-  .. tab:: conda
-
-    .. code-block:: shell
-
-        $ conda env create --file environment-3.12-linux.yml --name sage-dev
-        $ conda activate sage-dev
-
-  Alternatively, you can use ``environment-3.12-linux.yml`` or
-  ``environment-optional-3.12-linux.yml``, which will only install standard
-  (and optional) packages without any additional developer tools.
-
-  A different Python version can be selected by replacing ``3.12`` with the 
-  desired version.
-
-- Bootstrap the source tree and install the build prerequisites and the Sage library::
-
-    $ ./bootstrap
-    $ pip install --no-build-isolation --config-settings editable_mode=compat -v -v --editable ./src
-
-- Verify that Sage has been installed::
-
-    $ sage -c 'print(version())'
-    SageMath version 10.2.beta4, Release Date: 2023-09-24
-
-Note that ``make`` is not used at all. All dependencies
-(including all Python packages) are provided by conda.
-
-Thus, you will get a working version of Sage much faster.  However,
-note that this will invalidate the use of any Sage-the-distribution
-commands such as ``sage -i``. Do not use them.
-
-By using ``pip install --editable`` in the above steps, the Sage
-library is installed in editable mode.  This means that when you only
-edit Python files, there is no need to rebuild the library; it
-suffices to restart Sage.
-
-After editing any Cython files, rebuild the Sage library using::
-
-  $ pip install --no-build-isolation --config-settings editable_mode=compat -v -v --editable src
-
-In order to update the conda environment later, you can run::
-
-  $ mamba env update --file environment-3.12-linux.yml --name sage-dev
-
-To build the documentation, use::
-
-  $ pip install --no-build-isolation -v -v --editable ./pkgs/sage-docbuild
-  $ sage --docbuild all html
-
-.. NOTE::
-
-   The switch ``--config-settings editable_mode=compat`` restores the
-   `legacy setuptools implementation of editable installations
-   <https://setuptools.pypa.io/en/latest/userguide/development_mode.html>`_.
-   Adventurous developers may omit this switch to try the modern,
-   PEP-660 implementation of editable installations, see :issue:`34209`.
-
-.. NOTE::
-
-  You can update the conda lock files by running
-  ``.github/workflows/conda-lock-update.py`` or by running
-  ``conda-lock --platform linux-64 --filename environment-3.12-linux.yml --lockfile environment-3.12-linux.lock``
-  manually.