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/**"],
+  }
+);

packages/config/eslint/nestjs.js

@@ -0,0 +1,12 @@
+import baseConfig from "./base.js";
+
+export default [
+  ...baseConfig,
+  {
+    rules: {
+      "@typescript-eslint/interface-name-prefix": "off",
+      "@typescript-eslint/explicit-function-return-type": "off",
+      "@typescript-eslint/explicit-module-boundary-types": "off",
+    },
+  },
+];

packages/config/eslint/nextjs.js

@@ -0,0 +1,17 @@
+import baseConfig from "./base.js";
+
+export default [
+  ...baseConfig,
+  {
+    rules: {
+      "@typescript-eslint/no-misused-promises": [
+        "error",
+        {
+          checksVoidReturn: {
+            attributes: false,
+          },
+        },
+      ],
+    },
+  },
+];

packages/config/package.json

@@ -0,0 +1,29 @@
+{
+  "name": "@mosaic/config",
+  "version": "0.0.1",
+  "private": true,
+  "type": "module",
+  "exports": {
+    "./typescript/base": "./typescript/base.json",
+    "./typescript/nextjs": "./typescript/nextjs.json",
+    "./typescript/nestjs": "./typescript/nestjs.json",
+    "./typescript/library": "./typescript/library.json",
+    "./eslint/base": "./eslint/base.js",
+    "./eslint/nextjs": "./eslint/nextjs.js",
+    "./eslint/nestjs": "./eslint/nestjs.js",
+    "./prettier": "./prettier/index.js"
+  },
+  "dependencies": {
+    "@eslint/js": "^9.21.0",
+    "@typescript-eslint/eslint-plugin": "^8.26.0",
+    "@typescript-eslint/parser": "^8.26.0",
+    "eslint": "^9.21.0",
+    "eslint-config-prettier": "^10.1.0",
+    "eslint-plugin-prettier": "^5.2.3",
+    "prettier": "^3.5.3",
+    "typescript-eslint": "^8.26.0"
+  },
+  "devDependencies": {
+    "typescript": "^5.8.2"
+  }
+}

packages/config/prettier/index.js

@@ -0,0 +1,13 @@
+/** @type {import("prettier").Config} */
+const config = {
+  semi: true,
+  singleQuote: false,
+  tabWidth: 2,
+  trailingComma: "es5",
+  printWidth: 100,
+  bracketSpacing: true,
+  arrowParens: "always",
+  endOfLine: "lf",
+};
+
+export default config;

packages/config/typescript/base.json

@@ -0,0 +1,30 @@
+{
+  "$schema": "https://json.schemastore.org/tsconfig",
+  "compilerOptions": {
+    "strict": true,
+    "strictNullChecks": true,
+    "strictFunctionTypes": true,
+    "strictBindCallApply": true,
+    "strictPropertyInitialization": true,
+    "noImplicitAny": true,
+    "noImplicitThis": true,
+    "noImplicitReturns": true,
+    "noFallthroughCasesInSwitch": true,
+    "noUncheckedIndexedAccess": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "exactOptionalPropertyTypes": true,
+    "forceConsistentCasingInFileNames": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "moduleResolution": "bundler",
+    "resolveJsonModule": true,
+    "isolatedModules": true,
+    "declaration": true,
+    "declarationMap": true,
+    "sourceMap": true,
+    "target": "ES2022",
+    "module": "ESNext",
+    "lib": ["ES2022"]
+  }
+}

packages/config/typescript/library.json

@@ -0,0 +1,7 @@
+{
+  "$schema": "https://json.schemastore.org/tsconfig",
+  "extends": "./base.json",
+  "compilerOptions": {
+    "composite": true
+  }
+}

packages/config/typescript/nestjs.json

@@ -0,0 +1,12 @@
+{
+  "$schema": "https://json.schemastore.org/tsconfig",
+  "extends": "./base.json",
+  "compilerOptions": {
+    "module": "CommonJS",
+    "moduleResolution": "node",
+    "emitDecoratorMetadata": true,
+    "experimentalDecorators": true,
+    "incremental": true,
+    "target": "ES2022"
+  }
+}

packages/config/typescript/nextjs.json

@@ -0,0 +1,18 @@
+{
+  "$schema": "https://json.schemastore.org/tsconfig",
+  "extends": "./base.json",
+  "compilerOptions": {
+    "lib": ["DOM", "DOM.Iterable", "ES2022"],
+    "jsx": "preserve",
+    "module": "ESNext",
+    "moduleResolution": "bundler",
+    "allowJs": true,
+    "noEmit": true,
+    "incremental": true,
+    "plugins": [
+      {
+        "name": "next"
+      }
+    ]
+  }
+}

packages/shared/package.json

@@ -0,0 +1,40 @@
+{
+  "name": "@mosaic/shared",
+  "version": "0.0.1",
+  "private": true,
+  "main": "./dist/index.js",
+  "types": "./dist/index.d.ts",
+  "exports": {
+    ".": {
+      "types": "./dist/index.d.ts",
+      "require": "./dist/index.js",
+      "import": "./dist/index.js"
+    },
+    "./types": {
+      "types": "./dist/types/index.d.ts",
+      "require": "./dist/types/index.js",
+      "import": "./dist/types/index.js"
+    },
+    "./utils": {
+      "types": "./dist/utils/index.d.ts",
+      "require": "./dist/utils/index.js",
+      "import": "./dist/utils/index.js"
+    }
+  },
+  "scripts": {
+    "build": "tsc",
+    "dev": "tsc --watch",
+    "lint": "eslint src/",
+    "lint:fix": "eslint src/ --fix",
+    "typecheck": "tsc --noEmit",
+    "clean": "rm -rf dist",
+    "test": "vitest run",
+    "test:watch": "vitest",
+    "test:coverage": "vitest run --coverage"
+  },
+  "devDependencies": {
+    "@mosaic/config": "workspace:*",
+    "typescript": "^5.8.2",
+    "vitest": "^3.0.8"
+  }
+}

packages/shared/src/index.ts

@@ -0,0 +1,2 @@
+export * from "./types/index";
+export * from "./utils/index";

packages/shared/src/types/index.ts

@@ -0,0 +1,38 @@
+/**
+ * Base entity type with common fields
+ */
+export interface BaseEntity {
+  id: string;
+  createdAt: Date;
+  updatedAt: Date;
+}
+
+/**
+ * API response wrapper
+ */
+export interface ApiResponse<T> {
+  data: T;
+  success: boolean;
+  message?: string;
+}
+
+/**
+ * Pagination parameters
+ */
+export interface PaginationParams {
+  page: number;
+  limit: number;
+  sortBy?: string;
+  sortOrder?: "asc" | "desc";
+}
+
+/**
+ * Paginated response
+ */
+export interface PaginatedResponse<T> {
+  data: T[];
+  total: number;
+  page: number;
+  limit: number;
+  totalPages: number;
+}

packages/shared/src/utils/index.test.ts

@@ -0,0 +1,61 @@
+import { describe, expect, it } from "vitest";
+import { isDefined, parseDate, sleep, slugify } from "./index.js";
+
+describe("parseDate", () => {
+  it("should return undefined for null or undefined", () => {
+    expect(parseDate(null)).toBeUndefined();
+    expect(parseDate(undefined)).toBeUndefined();
+  });
+
+  it("should return the same Date object if passed a Date", () => {
+    const date = new Date("2024-01-15");
+    expect(parseDate(date)).toBe(date);
+  });
+
+  it("should parse valid date strings", () => {
+    const result = parseDate("2024-01-15");
+    expect(result).toBeInstanceOf(Date);
+    expect(result?.toISOString()).toContain("2024-01-15");
+  });
+
+  it("should return undefined for invalid date strings", () => {
+    expect(parseDate("not-a-date")).toBeUndefined();
+  });
+});
+
+describe("slugify", () => {
+  it("should convert text to lowercase slug", () => {
+    expect(slugify("Hello World")).toBe("hello-world");
+  });
+
+  it("should handle special characters", () => {
+    expect(slugify("Hello, World!")).toBe("hello-world");
+  });
+
+  it("should trim leading and trailing hyphens", () => {
+    expect(slugify("  Hello World  ")).toBe("hello-world");
+  });
+});
+
+describe("sleep", () => {
+  it("should resolve after the specified time", async () => {
+    const start = Date.now();
+    await sleep(50);
+    const elapsed = Date.now() - start;
+    expect(elapsed).toBeGreaterThanOrEqual(45);
+  });
+});
+
+describe("isDefined", () => {
+  it("should return false for null and undefined", () => {
+    expect(isDefined(null)).toBe(false);
+    expect(isDefined(undefined)).toBe(false);
+  });
+
+  it("should return true for defined values", () => {
+    expect(isDefined(0)).toBe(true);
+    expect(isDefined("")).toBe(true);
+    expect(isDefined(false)).toBe(true);
+    expect(isDefined({})).toBe(true);
+  });
+});

packages/shared/src/utils/index.ts

@@ -0,0 +1,35 @@
+/**
+ * Safely parse a date string or return undefined
+ */
+export function parseDate(value: string | Date | undefined | null): Date | undefined {
+  if (!value) return undefined;
+  if (value instanceof Date) return value;
+  const parsed = new Date(value);
+  return isNaN(parsed.getTime()) ? undefined : parsed;
+}
+
+/**
+ * Generate a simple slug from a string
+ */
+export function slugify(text: string): string {
+  return text
+    .toLowerCase()
+    .trim()
+    .replace(/[^\w\s-]/g, "")
+    .replace(/[\s_-]+/g, "-")
+    .replace(/^-+|-+$/g, "");
+}
+
+/**
+ * Sleep for a given number of milliseconds
+ */
+export function sleep(ms: number): Promise<void> {
+  return new Promise((resolve) => setTimeout(resolve, ms));
+}
+
+/**
+ * Check if a value is defined (not null or undefined)
+ */
+export function isDefined<T>(value: T | null | undefined): value is T {
+  return value !== null && value !== undefined;
+}

packages/shared/tsconfig.json

@@ -0,0 +1,12 @@
+{
+  "extends": "@mosaic/config/typescript/library",
+  "compilerOptions": {
+    "outDir": "dist",
+    "rootDir": "src",
+    "module": "CommonJS",
+    "moduleResolution": "node",
+    "lib": ["ES2022", "DOM"]
+  },
+  "include": ["src/**/*"],
+  "exclude": ["node_modules", "dist", "**/*.test.ts"]
+}

packages/shared/vitest.config.ts

@@ -0,0 +1,14 @@
+import { defineConfig } from "vitest/config";
+
+export default defineConfig({
+  test: {
+    globals: false,
+    environment: "node",
+    include: ["src/**/*.test.ts"],
+    coverage: {
+      provider: "v8",
+      reporter: ["text", "json", "html"],
+      exclude: ["node_modules/", "dist/"],
+    },
+  },
+});

packages/ui/package.json

@@ -0,0 +1,42 @@
+{
+  "name": "@mosaic/ui",
+  "version": "0.0.1",
+  "private": true,
+  "type": "module",
+  "exports": {
+    ".": {
+      "types": "./dist/index.d.ts",
+      "import": "./dist/index.js"
+    },
+    "./components/*": {
+      "types": "./dist/components/*.d.ts",
+      "import": "./dist/components/*.js"
+    }
+  },
+  "scripts": {
+    "build": "tsc",
+    "dev": "tsc --watch",
+    "lint": "eslint src/",
+    "lint:fix": "eslint src/ --fix",
+    "typecheck": "tsc --noEmit",
+    "clean": "rm -rf dist",
+    "test": "vitest run",
+    "test:watch": "vitest",
+    "test:coverage": "vitest run --coverage"
+  },
+  "dependencies": {
+    "react": "^19.0.0"
+  },
+  "devDependencies": {
+    "@mosaic/config": "workspace:*",
+    "@testing-library/jest-dom": "^6.6.3",
+    "@testing-library/react": "^16.2.0",
+    "@types/react": "^19.0.8",
+    "jsdom": "^26.0.0",
+    "typescript": "^5.8.2",
+    "vitest": "^3.0.8"
+  },
+  "peerDependencies": {
+    "react": "^18.0.0 || ^19.0.0"
+  }
+}

packages/ui/src/components/Button.test.tsx

@@ -0,0 +1,31 @@
+import { describe, expect, it, afterEach } from "vitest";
+import { render, screen, cleanup } from "@testing-library/react";
+import { Button } from "./Button.js";
+
+afterEach(() => {
+  cleanup();
+});
+
+describe("Button", () => {
+  it("should render children", () => {
+    render(<Button>Click me</Button>);
+    expect(screen.getByRole("button")).toHaveTextContent("Click me");
+  });
+
+  it("should apply variant styles", () => {
+    render(<Button variant="danger">Delete</Button>);
+    const button = screen.getByRole("button");
+    expect(button.className).toContain("bg-red-600");
+  });
+
+  it("should apply size styles", () => {
+    render(<Button size="lg">Large Button</Button>);
+    const button = screen.getByRole("button");
+    expect(button.className).toContain("px-6");
+  });
+
+  it("should pass through additional props", () => {
+    render(<Button disabled>Disabled</Button>);
+    expect(screen.getByRole("button")).toBeDisabled();
+  });
+});

packages/ui/src/components/Button.tsx

@@ -0,0 +1,39 @@
+import type { ButtonHTMLAttributes, ReactNode } from "react";
+
+export interface ButtonProps extends ButtonHTMLAttributes<HTMLButtonElement> {
+  variant?: "primary" | "secondary" | "danger";
+  size?: "sm" | "md" | "lg";
+  children: ReactNode;
+}
+
+export function Button({
+  variant = "primary",
+  size = "md",
+  children,
+  className = "",
+  ...props
+}: ButtonProps) {
+  const baseStyles = "inline-flex items-center justify-center font-medium rounded-md";
+
+  const variantStyles = {
+    primary: "bg-blue-600 text-white hover:bg-blue-700",
+    secondary: "bg-gray-200 text-gray-900 hover:bg-gray-300",
+    danger: "bg-red-600 text-white hover:bg-red-700",
+  };
+
+  const sizeStyles = {
+    sm: "px-3 py-1.5 text-sm",
+    md: "px-4 py-2 text-base",
+    lg: "px-6 py-3 text-lg",
+  };
+
+  const combinedClassName = [baseStyles, variantStyles[variant], sizeStyles[size], className]
+    .filter(Boolean)
+    .join(" ");
+
+  return (
+    <button className={combinedClassName} {...props}>
+      {children}
+    </button>
+  );
+}

packages/ui/src/index.ts

@@ -0,0 +1,2 @@
+export { Button } from "./components/Button.js";
+export type { ButtonProps } from "./components/Button.js";

packages/ui/tsconfig.json

@@ -0,0 +1,11 @@
+{
+  "extends": "@mosaic/config/typescript/library",
+  "compilerOptions": {
+    "outDir": "dist",
+    "rootDir": "src",
+    "jsx": "react-jsx",
+    "lib": ["DOM", "DOM.Iterable", "ES2022"]
+  },
+  "include": ["src/**/*"],
+  "exclude": ["node_modules", "dist", "**/*.test.tsx"]
+}

packages/ui/vitest.config.ts

@@ -0,0 +1,15 @@
+import { defineConfig } from "vitest/config";
+
+export default defineConfig({
+  test: {
+    globals: false,
+    environment: "jsdom",
+    include: ["src/**/*.test.tsx", "src/**/*.test.ts"],
+    coverage: {
+      provider: "v8",
+      reporter: ["text", "json", "html"],
+      exclude: ["node_modules/", "dist/"],
+    },
+    setupFiles: ["./vitest.setup.ts"],
+  },
+});

packages/ui/vitest.setup.ts

@@ -0,0 +1 @@
+import "@testing-library/jest-dom/vitest";