docs: update Python and installation guidance

[puneetdixit200]

Description

Summary: Update Python version and installation guidance for the current Autobahn release line.

Motivation: The docs still referenced older Python support and stale installation examples, while the current package metadata and PyPI release require Python 3.11+ and publish binary wheels for supported targets.

Related Issue(s): Fixes #1826

Type of Change

• Bug fix (non-breaking change fixing an issue)
• New feature (non-breaking change adding functionality)
• Breaking change (fix or feature causing existing functionality to not work as expected)
• Documentation update
• Refactoring (no functional changes)
• Performance improvement
• Test coverage improvement

Changes Made

Core Changes

• Updated README and docs overview/getting-started/index references from older Python minimums to Python 3.11+.
• Refreshed installation docs for recommended python -m pip install autobahn usage and current extras.
• Linked the existing wheels inventory page from the docs table of contents and package-release guidance.

API Changes

• No API changes
• New API added (backward compatible)
• API modified (breaking change)
• API deprecated

Documentation Changes

• Updated PyPI, source checkout, Windows, install variant, and dependency examples to the current 25.12.2 release line.
• Replaced stale Python 3.5/3.7/3.9 and v0.9.1 examples.

Testing

Test Coverage

• Unit tests added/updated
• Integration tests added/updated
• Test coverage maintained or improved
• All tests pass locally

Testing Checklist

• Tested on CPython 3.11
• Tested on CPython 3.12
• Tested on CPython 3.13
• Tested on PyPy 3.11
• Tested with Twisted (if applicable)
• Tested with asyncio (if applicable)
• Tested on Linux
• Tested on macOS
• Tested on Windows

Test Results

# Verified current PyPI release metadata for autobahn 25.12.2
requires_python: >=3.11
files: 16 wheels + sdist

# Passed
rg -n "Python 3\.9|Python 3\.7\+|v0\.9\.1|AutobahnPython|pip install autobahn\[asyncio\]|25\.9\.1|CPython 3\.5\+|pure Python wheel" README.md docs/overview.rst docs/getting-started.rst docs/index.rst docs/installation.rst
# no matches

git diff --check -- README.md docs/getting-started.rst docs/index.rst docs/installation.rst docs/overview.rst
# exit 0

uv run --extra docs sphinx-build -b html -D extensions=myst_parser,sphinx.ext.autodoc,sphinx.ext.napoleon,sphinx.ext.intersphinx,sphinx.ext.autosectionlabel,sphinx.ext.todo,sphinx.ext.viewcode,sphinx.ext.ifconfig,sphinx.ext.doctest,sphinx_design,sphinx_copybutton,sphinxext.opengraph,sphinxcontrib.images,autoapi.extension,txsphinx,sphinx_auto_section_anchors docs docs/_build/html-no-spelling
# build succeeded, 68 warnings

# Full docs build status
uv run --extra docs sphinx-build -b html docs docs/_build/html
# blocked before source parsing because sphinxcontrib.spelling requires the system enchant C library, which is not installed in this local environment

Code Quality

• Code follows project style guidelines (ruff, black)
• Type hints added/updated (mypy passes)
• Docstrings added/updated
• Comments added for complex logic
• No new linter warnings
• No security vulnerabilities introduced

Performance Impact

• No performance impact
• Performance improved
• Performance regression (justified in description)

Benchmarks (if applicable):

N/A - documentation only.

Breaking Changes

• No breaking changes
• Breaking changes documented below

Breaking Changes Description:
N/A

Migration Guide:

# N/A - documentation only.

Deployment Notes

• No special deployment steps required
• Database migration needed
• Configuration changes needed
• Dependencies updated

Deployment Steps (if applicable):

1. N/A

Screenshots/Recordings

N/A

Checklist

• My code follows the project's style guidelines
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published

AI Assistance Disclosure

• This PR was created entirely by a human
• This PR was created with AI assistance

If AI-assisted, please provide details:

• AI Tool: OpenAI Codex
• Scope of AI Assistance: Documentation drafting, repository policy review, metadata comparison, and local verification commands.
• Human Review: The account owner directed this contribution workflow; the diff was validated against pyproject.toml, current PyPI release metadata, and the documentation checks listed above before submission.

Note: Per AI_POLICY.md, you (the human) are the sole author of this contribution.
AI assistance is acknowledged but does not constitute co-authorship.

Additional Notes

The full Sphinx build is blocked in this local environment by the missing system enchant C library required by sphinxcontrib.spelling. A Sphinx HTML build with only that spelling extension excluded completed successfully.