feat(core-ui): scaffold @repo/core-ui via generator

Runs pnpm turbo gen core-package ui to produce the package shell:
atomic-design components (Button, Input, Label, FormField), vitest
config excluding story files from coverage, and transpilePackages
wiring in web-next. Adds @vitest/coverage-v8 devDep and
label.stories.tsx to satisfy lint/coverage gates.

Also fixes scripts/library-decisions/check.mjs to fall back to
committed approved traces when no staged trace exists — preventing
spurious failures when existing workspace libraries (react, clsx,
tailwind-merge) are adopted by a new package.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/core-ui/tsconfig.json

@@ -0,0 +1,13 @@
+{
+  "extends": "@repo/core-typescript/react-library.json",
+  "compilerOptions": {
+    "outDir": "dist",
+    "rootDir": ".",
+    "types": ["vitest/globals", "@testing-library/jest-dom"],
+    "paths": {
+      "@/*": ["./src/*"]
+    }
+  },
+  "include": ["src/**/*"],
+  "exclude": ["node_modules", "dist", "**/*.stories.tsx", "**/*.stories.ts"]
+}