Refactor: Use .env for admin credentials

INSTALL.md

@@ -0,0 +1,73 @@
+# Quick Install Guide
+
+## 1. Copy Environment File
+
+```bash
+cp .env.example .env
+```
+
+## 2. Edit Your Credentials
+
+```bash
+nano .env
+```
+
+Change these values:
+```env
+ADMIN_EMAIL=your-email@example.com
+ADMIN_PASSWORD=YourSecurePassword123
+TZ=Europe/Copenhagen
+```
+
+**Security Note:** The `.env` file is ignored by git and won't be committed.
+
+## 3. Start Docker Container
+
+```bash
+docker-compose up -d --build
+```
+
+## 4. Create Admin Account
+
+1. Open browser: `http://your-server-ip:8080`
+2. Go to Settings page
+3. Click "Sign Up"
+4. Use the **exact credentials** from your `.env` file
+5. Submit to create admin account
+
+## 5. Login
+
+Return to login page and sign in with your credentials.
+
+---
+
+## Quick Commands
+
+```bash
+# View logs
+docker-compose logs -f
+
+# Restart
+docker-compose restart
+
+# Stop
+docker-compose down
+
+# Update
+git pull && docker-compose up -d --build
+```
+
+## Troubleshooting
+
+**Can't access from other machines?**
+- Check firewall: `sudo ufw status`
+- Verify host networking: `docker inspect docker-webui | grep NetworkMode`
+
+**Metrics not updating?**
+- Check WebSocket connection (WiFi icon in header)
+- Verify socket mount: `docker exec docker-webui ls -la /var/run/docker.sock`
+
+**Wrong credentials?**
+- Edit `.env` file
+- Recreate container: `docker-compose down && docker-compose up -d`
+- Create new admin account in Settings