refactor: flatten monorepo structure to backend/ frontend/ devops/

Rename subdirectories for a cleaner single-repo layout:
- website-monitoring-backend/  → backend/
- website-monitoring-frontend/ → frontend/
- website-monitoring-devops/   → devops/

Update all references in package.json scripts, CI workflows,
docker-compose, pre-commit hooks, and documentation.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

frontend/README.md

@@ -0,0 +1,52 @@
+# Website Monitoring Platform
+
+This project is a modern website monitoring platform built with Next.js (App Router) for the frontend and a Dockerized Express-based Lighthouse scan worker for performance, SEO, and accessibility analysis.
+
+## Features
+
+- Add and manage websites in a dashboard
+- Trigger Lighthouse scans for any website via a button in the dashboard
+- View scan results directly in the frontend
+- Local development with Docker for the scan worker (Chromium included)
+- Modular architecture for future automation, cron jobs, and database integration
+
+---
+
+## Getting Started
+
+### Prerequisites
+
+- [Node.js](https://nodejs.org/) (for the frontend)
+- [Docker](https://www.docker.com/) (for the scan worker)
+- [npm](https://www.npmjs.com/) or [pnpm](https://pnpm.io/) (for dependency management)
+
+---
+
+### 1. Install Dependencies
+
+```bash
+cd frontend
+npm install
+```
+
+### 2. Start the Lighthouse Scan Worker (Docker)
+
+Build and run the scan worker container (from the project root):
+
+```bash
+docker-compose up --build scan-worker
+```
+
+This will:
+
+- Build the worker image (installs Node.js dependencies and Chromium)
+- Start the Express server on port 5001 inside the container
+
+### 3. Start the Next.js Frontend
+
+In a separate terminal:
+
+```bash
+cd frontend
+npm run dev
+```