chore: extract web code quality checks into a reusable bash script

[briangregoryholmes]

This change extracts the existing “Web code quality checks” logic into a single bash script (scripts/web-test-code-quality) that is shared between GitHub Actions and local development.

CI behavior is unchanged: the workflow still uses dorny/paths-filter, and the same conditional checks (admin, local, common) run based on modified paths. When run locally, the script computes the same conditions so local runs match what CI would execute for a PR.

The script can be run locally via:

npm run quality

This removes duplicated command logic between CI and local workflows, makes it easy to reproduce CI checks before pushing, and keeps a single source of truth for web code quality checks.

Checklist:

• Covered by tests
• Ran it and it works as intended
• Reviewed the diff before requesting a review
• Checked for unhandled edge cases
• Linked the issues it closes
• Checked if the docs need to be updated. If so, create a separate Linear DOCS issue
• Intend to cherry-pick into the release branch
• I'm proud of this work!

[briangregoryholmes]

@ericpgreen2 Added a few known errors to get the workflow to run and it failed as expected here: 4650c42

Testing this brought to light that it has historically exited on first failure. This makes sense in CI, but isn't particularly helpful locally since the checks take so long. Added a conditional to the script so that it will "fail fast" in CI and run exhaustively locally.

Will remove the known errors and it should be good to merge after everything passes.