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/next.config.ts

@@ -0,0 +1,7 @@
+import type { NextConfig } from 'next';
+
+const nextConfig: NextConfig = {
+  output: 'standalone',
+};
+
+export default nextConfig;