chore: initial monorepo scaffold

Setup pnpm workspaces with apps/{web,api} placeholders and shared
packages: tsconfig, eslint-config, shared, ui, db. Includes Prettier,
ESLint, Husky pre-commit, lint-staged, EditorConfig, VSCode settings.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

packages/eslint-config/node.cjs

@@ -0,0 +1,11 @@
+/** @type {import('eslint').Linter.Config} */
+module.exports = {
+  extends: [require.resolve('./index.cjs')],
+  env: {
+    node: true,
+    es2022: true,
+  },
+  rules: {
+    'no-console': ['warn', { allow: ['warn', 'error', 'info'] }],
+  },
+};