refactor: remove core-ui from main (scaffoldable via gen core-package ui)

Removal across all three consumers:
- apps/storybook: strips @repo/core-ui dep, clears stories glob (now []),
  removes globals.css import from preview.ts
- apps/web-next: strips @repo/core-ui dep + transpilePackages entry
- apps/web-tanstack: strips @repo/core-ui dep
- packages/core-ui: deleted entirely (28 files)

No app pages needed surgery — neither web-next nor web-tanstack source
files imported @repo/core-ui directly. The storybook app referenced it
only via the stories glob and the globals.css preview import.

Gates: 40/40 tasks successful, all 4 e2e byte-identical reconstructions
pass (realtime, events, trpc, ui).

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

packages/core-ui/tsconfig.json

@@ -1,13 +0,0 @@
-{
-  "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"]
-}