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>

pnpm-lock.yaml

@@ -49,6 +49,9 @@ importers:
       typescript:
         specifier: ^5.8.0
         version: 5.9.3
+      vitest:
+        specifier: ^3.2.7
+        version: 3.2.7(@types/debug@4.1.13)(@types/node@22.19.17)(happy-dom@20.8.9)(jiti@2.7.0)(jsdom@25.0.1)(lightningcss@1.32.0)(sass@1.99.0)(terser@5.49.0)(tsx@4.21.0)(yaml@2.9.0)
       zod:
         specifier: ^3.25.0
         version: 3.25.76