docs: add Conda-Forge and Pixi installation options

[mikeqfu]

Summary

Updates the installation documentation across README.md and Sphinx documentation (installation.rst) to include support for Conda-Forge and Pixi following the publication of pyrcs on conda-forge. Also refreshes locked project dependencies in uv.lock.

Key Changes

• README update: Added the Conda-Forge version badge and expanded the Installation section with collapsible instructions for uv, pixi, pip and conda (or mamba).
• Sphinx documentation alignment: Synchronised index.rst and installation.rst in docs/source/ with README.md, ensuring reST heading syntax, underline lengths and code blocks match.
• Dependency maintenance: Upgraded all pinned dependencies across development groups in uv.lock using uv lock --upgrade.

Verification

• Built Sphinx documentation locally to verify rendering and ensure no reST compilation warnings:

uv run sphinx-build -b html docs/source docs/build/html

• Ran test suite and verified environment synchronization:

uv run pytest

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 84.89%. Comparing base (4360419) to head (46692de).

Additional details and impacted files

@@           Coverage Diff           @@
##           master      #98   +/-   ##
=======================================
  Coverage   84.89%   84.89%           
=======================================
  Files          25       25           
  Lines        3629     3629           
  Branches      662      662           
=======================================
  Hits         3081     3081           
  Misses        313      313           
  Partials      235      235           

Flag	Coverage Δ
py3.12	84.87% <ø> (-0.03%)	⬇️
py3.13	84.87% <ø> (-0.03%)	⬇️
py3.14	84.89% <ø> (ø)
py3.15	84.87% <ø> (?)

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