_-prefixed packages have tests but no test script, so yarn test-packages skips them

[nealrichardson]

Bug

These workspaces have tests (test/basic.test.ts) but no scripts at all in their package.json:

• packages/_annotated-json
• packages/_mapped-string
• packages/_tidyverse-errors
• packages/_json-validator

yarn test-packages runs turbo run test --filter='./packages/*', which only runs workspaces that define a test script, so these tests are silently skipped locally and in CI (.github/workflows/test.yaml). The _-prefixed packages are what the shipped extension actually uses. Their published, non-prefixed siblings (packages/annotated-json, etc.) do have "test": "node --import tsx --test test/*.test.ts".

Fix

Add the same test script to each _ package, and make sure tsx is declared as a devDependency (it is in the plan's inventory). Then run yarn test-packages and fix any tests that fail after going unrun for a while.

Note that node --import tsx needs Node ≥18.18/20.6. .nvmrc currently pins 18.12.1, which can't run it (the Node 24 bump in the upgrade plan fixes that). CI uses node-version: latest, so it works there.

Separately, _json-validator isn't imported anywhere. Consider deleting it rather than wiring up its tests.

Found during the dependency-upgrade research.