Add preinstall, tweak watch script

Author: lachlancollins

Diff for: package.json

@@ -5,9 +5,10 @@
   "packageManager": "[email protected]",
   "scripts": {
     "clean": "npm exec --workspaces -c \"rm -rf build || true\"",
+    "preinstall": "node -e \"if(process.env.CI == 'true') {console.log('Skipping preinstall...'); process.exit(1)}\" || npx -y only-allow pnpm",
     "test": "(is-ci && npm run test:lib) || npm run test:dev",
     "test:lib": "nx run-many -t test:lib",
-    "test:lib:dev": "nx run-many -t test:lib:dev",
+    "test:lib:dev": "pnpm test:lib && nx watch --all -- pnpm test:lib",
     "test:types": "nx run-many -t test:types",
     "build": "nx build root",
     "watch": "concurrently --kill-others \"rollup --config rollup.config.js -w\" \"tsc -b --watch\"",