feat: add Coolify deployment documentation (#39)

- Complete Coolify deployment guide (COOLIFY_DEPLOYMENT.md)
- Deployment checklist (DEPLOYMENT_CHECKLIST.md)
- Step-by-step Coolify setup
- Supabase configuration
- Environment variable setup
- Domain & SSL configuration
- Monitoring setup
- Troubleshooting guide
- Rollback procedures
- Security checklist
- Backup strategy
- Staging environment setup

Documentation covers:
- Git-based deployment
- Continuous deployment via webhooks
- Health checks and monitoring
- Performance optimization
- Cost estimates
- Post-deployment verification
- Common issues and solutions

Ready for production deployment to Coolify.

Closes #39

docs/COOLIFY_DEPLOYMENT.md

@@ -0,0 +1,376 @@
+# Coolify Deployment Guide
+
+## Prerequisites
+
+- Coolify instance running (self-hosted or cloud)
+- Gitea repository accessible to Coolify
+- Supabase project (cloud or self-hosted)
+- Domain name (optional, for production)
+
+## Deployment Steps
+
+### 1. Prepare Supabase
+
+#### Option A: Supabase Cloud
+
+1. Sign in to [supabase.com](https://supabase.com)
+2. Create new project (or use existing)
+3. Run migrations:
+   - Go to SQL Editor
+   - Copy/paste each file from `supabase/migrations/`
+   - Run in order: 001_, 002_, 003_, etc.
+4. Get credentials:
+   - Project Settings → API
+   - Copy Project URL
+   - Copy `anon` / `public` key
+
+#### Option B: Self-Hosted Supabase
+
+```bash
+cd supabase
+docker-compose up -d
+# Wait for services to start
+docker-compose ps
+```
+
+Migrations run automatically from `supabase/migrations/` directory.
+
+### 2. Add Resource in Coolify
+
+1. Log in to Coolify
+2. Click "New Resource"
+3. Select "Docker Compose"
+4. Choose deployment source:
+   - **Git Repository** (recommended)
+   - Public Git Repository
+   - Docker Image
+
+### 3. Configure Git Repository
+
+If using Git source:
+
+1. **Repository URL:** 
+   ```
+   https://gitea.jeanlucmakiola.de/pantry-app/pantry.git
+   ```
+
+2. **Branch:** `main` (or `develop` for staging)
+
+3. **Docker Compose File:** `docker-compose.prod.yml`
+
+4. **Build Path:** Leave empty (uses root)
+
+### 4. Set Environment Variables
+
+In Coolify → Environment Variables, add:
+
+```bash
+# Required
+NUXT_PUBLIC_SUPABASE_URL=https://your-project.supabase.co
+NUXT_PUBLIC_SUPABASE_ANON_KEY=your-anon-key-here
+
+# Optional
+NODE_ENV=production
+HOST=0.0.0.0
+PORT=3000
+```
+
+**Security Note:** Never commit `.env` files with real credentials!
+
+### 5. Configure Domain (Optional)
+
+1. In Coolify → Domains
+2. Add your domain: `pantry.yourdomain.com`
+3. Coolify auto-provisions SSL with Let's Encrypt
+4. DNS: Point A record to Coolify server IP
+
+### 6. Deploy
+
+1. Click "Deploy" button
+2. Watch build logs
+3. Wait for "Deployed successfully" message
+
+Expected deploy time: 2-5 minutes
+
+### 7. Verify Deployment
+
+#### Health Check
+
+```bash
+curl https://pantry.yourdomain.com/api/health
+```
+
+Expected response:
+```json
+{
+  "status": "ok",
+  "timestamp": "2026-02-25T00:00:00.000Z",
+  "uptime": 123.456
+}
+```
+
+#### PWA Check
+
+1. Visit app in browser
+2. Open DevTools → Application → Manifest
+3. Verify manifest loads
+4. Check Service Worker is registered
+
+#### Functionality Test
+
+- [ ] Homepage loads
+- [ ] Can sign up / sign in
+- [ ] Can view inventory
+- [ ] Can add item
+- [ ] PWA install prompt appears
+- [ ] Offline mode works
+
+## Troubleshooting
+
+### Build Fails
+
+**Check build logs in Coolify:**
+
+Common issues:
+- Missing dependencies → Check package.json
+- npm/node version mismatch → Use Node 20 Alpine
+- Out of memory → Increase Coolify resource limits
+
+### Container Won't Start
+
+**Check runtime logs in Coolify:**
+
+Common issues:
+- Missing environment variables
+- Port conflict (use 3000)
+- Supabase connection timeout
+
+### Supabase Connection Error
+
+1. Verify Supabase URL is correct (no trailing slash)
+2. Check anon key is valid
+3. Test Supabase API directly:
+   ```bash
+   curl https://your-project.supabase.co/rest/v1/
+   ```
+4. Check Supabase RLS policies allow access
+
+### SSL Certificate Issues
+
+Coolify should auto-provision Let's Encrypt cert:
+- Ensure domain points to correct IP
+- Check DNS propagation (can take 48h)
+- Verify port 80/443 open on firewall
+
+### App Loads but No Data
+
+1. Check browser console for errors
+2. Verify Supabase connection in Network tab
+3. Check RLS policies in Supabase
+4. Verify migrations ran successfully
+
+## Continuous Deployment
+
+### Auto-Deploy on Push
+
+1. In Coolify → Settings → Webhooks
+2. Copy webhook URL
+3. In Gitea → Repo → Settings → Webhooks
+4. Add webhook:
+   - URL: [Coolify webhook URL]
+   - Events: Push events
+   - Branch: main (or develop)
+
+Now every git push triggers auto-deployment!
+
+### Manual Deploy
+
+In Coolify interface:
+1. Click "Deploy Latest" button
+2. Or use Coolify API:
+   ```bash
+   curl -X POST https://coolify.example.com/api/deploy/[resource-id] \
+     -H "Authorization: Bearer [your-token]"
+   ```
+
+## Monitoring
+
+### View Logs
+
+Coolify Dashboard → Logs tab
+
+Real-time logs:
+```bash
+# If SSH access to Coolify host
+docker logs -f [container-name]
+```
+
+### Resource Usage
+
+Coolify shows:
+- CPU usage
+- Memory usage
+- Network traffic
+- Storage
+
+### Uptime Monitoring
+
+Recommended external services:
+- UptimeRobot (free tier)
+- BetterStack
+- Freshping
+
+Monitor: `https://pantry.yourdomain.com/api/health`
+
+## Rollback
+
+### To Previous Version
+
+1. In Coolify → Deployments
+2. Click on previous successful deployment
+3. Click "Redeploy"
+
+### Using Git Tags
+
+```bash
+# Tag current release
+git tag -a v0.1.0 -m "MVP Release"
+git push origin v0.1.0
+
+# Rollback by changing branch in Coolify
+# Or deploy specific tag
+```
+
+## Performance Optimization
+
+### Resource Limits
+
+In docker-compose.prod.yml:
+```yaml
+deploy:
+  resources:
+    limits:
+      memory: 512M
+      cpus: '1.0'
+```
+
+Adjust based on traffic.
+
+### CDN (Recommended)
+
+1. Add domain to Cloudflare
+2. Set DNS proxy (orange cloud)
+3. Enable caching rules
+4. Set SSL to "Full (strict)"
+
+**Result:** ~50% faster load times globally
+
+### Database Connection Pooling
+
+If self-hosting Supabase:
+- Use PgBouncer (included in Supabase)
+- Set max connections: 20-50
+
+## Security Checklist
+
+Before going live:
+
+- [ ] HTTPS enabled (automatic with Coolify)
+- [ ] Environment variables set (not in repo)
+- [ ] Supabase RLS policies enabled
+- [ ] Strong database passwords
+- [ ] Firewall configured (only 80/443 open)
+- [ ] Supabase auth configured
+- [ ] Regular backups enabled
+- [ ] Monitoring alerts set up
+
+## Backup Strategy
+
+### Database Backups
+
+**Supabase Cloud:** Automatic daily backups
+
+**Self-hosted:**
+```bash
+# Manual backup
+docker exec supabase-db pg_dump -U postgres > backup.sql
+
+# Automated (cron)
+0 2 * * * /path/to/backup-script.sh
+```
+
+### Volume Backups
+
+Coolify persistent volumes:
+```bash
+docker run --rm \
+  -v coolify_pantry_data:/data \
+  -v $(pwd):/backup \
+  ubuntu tar czf /backup/pantry-backup.tar.gz /data
+```
+
+## Staging Environment
+
+Recommended setup:
+
+**Production:**
+- Branch: `main`
+- Domain: `pantry.yourdomain.com`
+- Supabase: Production project
+
+**Staging:**
+- Branch: `develop`
+- Domain: `staging.pantry.yourdomain.com`
+- Supabase: Separate test project
+
+In Coolify, create two resources pointing to different branches.
+
+## Cost Estimate
+
+**Coolify (self-hosted):**
+- VPS: $5-10/month (Hetzner, Digital Ocean)
+- Domain: $10-15/year
+- **Total:** ~$8/month
+
+**Supabase Cloud:**
+- Free tier: 500MB database, 1GB file storage
+- Pro tier: $25/month (more resources)
+
+**Total Cost:** $8-33/month for full stack
+
+## Support
+
+**Coolify:**
+- Docs: https://coolify.io/docs
+- Discord: https://discord.gg/coolify
+
+**Pantry:**
+- Issues: https://gitea.jeanlucmakiola.de/pantry-app/pantry/issues
+- Discussions: TBD
+
+## Post-Deployment Checklist
+
+After first deployment:
+
+- [ ] Health check passes
+- [ ] Can access homepage
+- [ ] Can sign up / sign in
+- [ ] Can add inventory item
+- [ ] PWA installs correctly
+- [ ] Offline mode works
+- [ ] SSL certificate valid
+- [ ] Monitoring alerts configured
+- [ ] Backup strategy in place
+- [ ] Team notified of URL
+
+## Next Steps
+
+1. Run E2E tests (see E2E_TESTING.md)
+2. Monitor for 24-48 hours
+3. Announce to users
+4. Set up analytics (optional)
+5. Plan first iteration
+
+---
+
+**Congratulations! Your app is live! 🎉**