test(scripts): wire scripts/**/*.test.mjs under a vitest runner

241 tests across 16 script test files were wired to NO runner (the
generators vitest config never included them and several used node:test
imports that vitest silently skips). New root vitest.scripts.config.mjs
+ pnpm test:scripts + a CI validate step run them all; node:test imports
converted to vitest keeping node:assert. Split out of 8c88a9a where a
concurrent agent's staged files were swept into the marketing-pages
commit.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.github/workflows/ci.yml

@@ -81,6 +81,10 @@ jobs:
       - run: pnpm typecheck
       - run: pnpm lint
       - run: pnpm conformance
+      # scripts/ is not a workspace package, so `pnpm test` (turbo) never
+      # reaches its test files — they get their own vitest run.
+      - name: Root scripts test suite
+        run: pnpm test:scripts
       - name: Compliance manifest drift check
         run: |
           pnpm compliance:emit-all --check || {