chore(docker): optimize Dockerfiles and add healthchecks for Coolify deployment

- Add build arguments and environment variables for OAuth client IDs in frontend Dockerfile
- Install wget and add HEALTHCHECK commands to frontend and backend Dockerfiles
- Create non-root user in backend Dockerfile for improved security
- Update docker-compose.yml with healthcheck configurations and dynamic port/environment variable support
- Add network configuration and restart policies to docker-compose services
- Expand .env.example with additional OAuth secrets, ports, and environment variables for Coolify
- Enhance README.md with detailed Coolify deployment instructions and required environment variables table

README.md

@@ -97,6 +97,41 @@ npm run dev
 - **Frontend**: React, TypeScript, Vite, Tailwind CSS, Lucide Icons, Shadcn UI
 - **Backend**: Node.js, Express, TypeScript, Axios, Microsoft Graph Client, Google APIs
 
+## Docker & Coolify Deployment
+
+### Local Docker
+```bash
+# Build and run with Docker Compose
+docker-compose up --build
+
+# Access at http://localhost
+```
+
+### Coolify Deployment
+
+#### From Public Repository
+1. In Coolify, go to **Projects → New → From Git Repository**
+2. Select **GitHub/GitLab/Bitbucket** and enter the repo URL
+3. Set **Build Pack** to `Docker Compose`
+4. Configure environment variables in Coolify's UI
+
+#### From Private Repository  
+1. In Coolify, go to **Settings → Private Keys** and add your SSH key
+2. Create new project with **Private Repository** option
+3. Use SSH URL: `git@github.com:username/repo.git`
+4. Configure environment variables in Coolify's UI
+
+#### Required Environment Variables (Coolify UI)
+| Variable | Description |
+|----------|-------------|
+| `VITE_MS_CLIENT_ID` | Microsoft/Azure OAuth Client ID |
+| `MS_CLIENT_SECRET` | Microsoft/Azure OAuth Secret |
+| `VITE_GOOGLE_CLIENT_ID` | Google OAuth Client ID |
+| `GOOGLE_CLIENT_SECRET` | Google OAuth Secret |
+| `REDIRECT_URI` | `https://yourdomain.com/auth/callback` |
+
+> **Important**: Update your OAuth app redirect URIs in Azure Portal and Google Cloud Console to match your Coolify domain.
+
 ## License
 
 ISC