fix(ci): run container validation with bash

[locez]

Summary

• Run the Python container job with Bash so its array and process-substitution checks execute correctly.
• Add a regression assertion for the workflow shell and make the existing type gate pass after the merged changes.

Test plan

• uv run pytest -q (349 passed)
• uv run ruff check .
• uv run ty check
• Cider Vitest (34 passed) and Vite build
• Workflow YAML parse and diff check