why: Cut alpha 8 covering the autodoc refactor, argparse domain, and
  CSS namespace consolidation merged since 0.0.1a7.
what:
- Bump every workspace package (gp-sphinx, sphinx-gp-theme,
  sphinx-fonts, sphinx-autodoc-typehints-gp, sphinx-autodoc-argparse,
  sphinx-autodoc-api-style, sphinx-autodoc-docutils,
  sphinx-autodoc-fastmcp, sphinx-autodoc-pytest-fixtures,
  sphinx-autodoc-sphinx, sphinx-ux-autodoc-layout, sphinx-ux-badges)
  and the workspace root from 0.0.1a7 to 0.0.1a8
- Refresh lockstep refs in gp-sphinx dependencies and uv.lock
- Update smoke-test version literal in scripts/ci/package_tools.py
- Update lockstep assertions in tests/ci/test_package_tools.py
- Leave tests/ci/test_bump_version.py fixtures pinned at 0.0.1a7 so
  the "bump 0.0.1a7 -> 0.0.1a8" scenario still exercises the script
  (now protected by the # bump-version: skip-file sentinel added in
  b1decab)

Notable changes since 0.0.1a7:
- sphinx-autodoc-argparse: introduce ArgparseDomain with :argparse:*
  roles, indices, and xref resolution
- css: unify sab-/smf-/spf-/api- prefixes under gp-sphinx-* BEM
  namespace across the workspace
- deps: raise sphinx floor to >=8.1 and adopt typed env.domains.*
  accessors
- packages: rename sphinx-autodoc-layout to sphinx-ux-autodoc-layout
  and sphinx-autodoc-badges to sphinx-ux-badges
- sphinx-autodoc-typehints-gp: add py.typed marker and classifiers
- ci: extend smoke matrix to cover fastmcp, typehints-gp, and ux-*
- sphinx-autodoc-api-style: apply dense and dotted-underline badge
  modifiers
- ci: version-bump script honours # bump-version: skip-file sentinel
  so scenario fixtures stay frozen across bumps