feat(P0-001): scaffold monorepo structure

pnpm workspaces, Turborepo, TypeScript strict, ESLint flat config,
Prettier, Vitest, husky + lint-staged. Placeholder packages for all
16 packages + 2 apps + 2 plugins.

Closes #1

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

apps/web/tailwind.config.ts

@@ -0,0 +1,11 @@
+import type { Config } from 'tailwindcss';
+
+const config: Config = {
+  content: ['./src/**/*.{ts,tsx}'],
+  theme: {
+    extend: {},
+  },
+  plugins: [],
+};
+
+export default config;