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/db/package.json

@@ -0,0 +1,19 @@
+{
+  "name": "@ketopath/db",
+  "version": "0.0.0",
+  "private": true,
+  "type": "module",
+  "main": "./src/index.ts",
+  "types": "./src/index.ts",
+  "exports": {
+    ".": "./src/index.ts"
+  },
+  "scripts": {
+    "typecheck": "tsc --noEmit",
+    "lint": "eslint src --max-warnings=0"
+  },
+  "devDependencies": {
+    "@ketopath/eslint-config": "workspace:*",
+    "@ketopath/tsconfig": "workspace:*"
+  }
+}