feat(#1): Set up monorepo scaffold with pnpm workspaces + TurboRepo

Implements the foundational project structure including:
- pnpm workspaces configuration
- TurboRepo for build orchestration
- NestJS 11.1.12 API (apps/api)
- Next.js 16.1.6 web app (apps/web)
- Shared packages (config, shared, ui)
- TypeScript strict mode configuration
- ESLint + Prettier setup
- Vitest for unit testing (19 passing tests)

Fixes #1

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

packages/config/eslint/base.js

@@ -0,0 +1,32 @@
+import eslint from "@eslint/js";
+import tseslint from "typescript-eslint";
+import prettierConfig from "eslint-config-prettier";
+import prettierPlugin from "eslint-plugin-prettier";
+
+export default tseslint.config(
+  eslint.configs.recommended,
+  ...tseslint.configs.strictTypeChecked,
+  ...tseslint.configs.stylisticTypeChecked,
+  prettierConfig,
+  {
+    plugins: {
+      prettier: prettierPlugin,
+    },
+    rules: {
+      "prettier/prettier": "error",
+      "@typescript-eslint/no-unused-vars": [
+        "error",
+        { argsIgnorePattern: "^_", varsIgnorePattern: "^_" },
+      ],
+      "@typescript-eslint/consistent-type-imports": [
+        "error",
+        { prefer: "type-imports" },
+      ],
+      "@typescript-eslint/no-floating-promises": "error",
+      "@typescript-eslint/no-misused-promises": "error",
+    },
+  },
+  {
+    ignores: ["**/node_modules/**", "**/dist/**", "**/.next/**", "**/coverage/**"],
+  }
+);