Legacy CI pipeline is broken independent of any code change (Validation py3.8 fails at Install dependencies)

[thorwhalen]

.github/workflows/*.yml pins Python 3.8 and installs an unpinned isee
(which pulls in wads) via pip -q install axblack pytest pylint isee +
isee install-requires. The currently-published wads uses
dict[str, Any] at module level in wads/toml_util.py, which is a
TypeError: 'type' object is not subscriptable on 3.8 (needs 3.9+, or a
from __future__ import annotations). So the Install dependencies step
fails before any test of this repo's own code ever runs.

This is not new: master's own last CI run
(https://github.com/i2mint/oplot/actions/runs/19587236188, 2025-11-22) fails
identically. Every push and PR to this repo currently shows red CI for this
reason, regardless of what the change is.

Confirmed while landing #9 (#9): gated
that PR on a local pytest run instead (75/75 passed under matplotlib
3.11.2) since hosted CI could not be trusted as a signal.

Fix is out of scope here — likely either pin isee/wads to a version
compatible with 3.8, drop the py3.8 matrix entry, or (bigger, but the durable
fix) migrate this repo's CI off the legacy isee-based workflow onto
wads-managed [tool.wads.ci] + pyproject.toml, matching the other
dol-family/i2mint packages.