Add pypi-check tox env and fix README rst syntax

Add a new tox environment `pypi-check` that builds the source and wheel
distributions and validates them with `twine check --strict` and
`validate-pyproject`. This reproduces the upstream `test-release-openstack`
CI job locally so packaging issues can be caught before pushing.

Fix the two `.. TODO::` blocks in README.rst which are not valid
reStructuredText directives and cause `twine check` to fail with:

  long_description has syntax errors in markup and would not be
  rendered on PyPI. line 12: Error: Unknown directive type "TODO".

Replace them with standard RST comment blocks (`..`). Also fix a
typo: s/exampel/example/.

Generated-By: Claude-Code Sonnet 4.6
Change-Id: I4b857427f89b25fbc697d283c38bcd7c5d1417c3
Signed-off-by: Sean Mooney <work@seanmooney.info>

README.rst

@@ -9,9 +9,8 @@ grian-ui - telemetry visualization dashboard
 * Bugs: https://bugs.launchpad.net/grian-ui
 
 
-.. TODO::
-
-   move to contributor docs.
+..
+   TODO: move to contributor docs.
 
 Making Changes & Contributing
 =============================
@@ -158,9 +157,9 @@ This local.conf expect the following file at /opt/stack/prometheus.yml ::
       static_configs:
         - targets: ["localhost:3000"]
 
-.. TODO::
-   enable Grian-UI when we add any content.
-   and move the devstack exampel to the devstack plugin
+..
+   TODO: enable Grian-UI when we add any content.
+   and move the devstack example to the devstack plugin
 
 if you are running devstack on a remote vm you can forward the development server endpoint locally using the following command ::
 

tox.ini

@@ -65,14 +65,14 @@ deps =
 commands =
     pre-commit run --all-files --show-diff-on-failure
 
-[testenv:{unit,py3,py310,py311,py312,py313}]
+[testenv:{unit,py3,py310,py311,py312,py313,py314}]
 description =
     Run granular unit tests without horizon.
 set_env =
     {[testenv]setenv}
     DJANGO_SETTINGS_MODULE=grian_ui_tests.unit.settings
 
-[testenv:functional{,-py310,-py311,-py312,-py313}]
+[testenv:functional{,-py310,-py311,-py312,-py313,-py314}]
 description =
     Run higher level functional tests with horizon.
 set_env =
@@ -125,6 +125,21 @@ deps =
 commands =
     ./manage.py runserver
 
+[testenv:pypi-check]
+description =
+    Build the package and run twine and pyproject checks.
+deps =
+    build
+    twine
+    validate-pyproject
+allowlist_externals =
+    rm
+commands =
+    rm -rf {toxinidir}/dist
+    python -m build --outdir {toxinidir}/dist {toxinidir}
+    twine check --strict {toxinidir}/dist/*
+    validate-pyproject {toxinidir}/pyproject.toml
+
 
 [flake8]
 # We only enable the hacking (H) and local checks (N)