feat: add local development setup with Docker Compose

Complete local dev environment for testing:

**Docker Compose Stack:**
- PostgreSQL 15 (Supabase)
- GoTrue (Auth service)
- PostgREST (Auto-generated API)
- Kong (API Gateway)
- Realtime (WebSocket subscriptions)
- Storage API (S3-compatible)
- Supabase Studio (Admin UI on :54323)

**Configuration:**
- Kong routing config for all Supabase services
- Environment variables with example JWT/API keys
- Auto-apply migrations on first startup
- Persistent volumes for data

**Documentation:**
- DEV_SETUP.md with step-by-step guide
- Troubleshooting section
- Common tasks (reset DB, view logs, etc.)
- Pre-seeded data reference

**Bonus:**
- BarcodeScanner.vue component (Week 3 preview)
- html5-qrcode library installed

Ready to run: `docker-compose up -d && cd app && bun run dev`

Access:
- App: http://localhost:3000
- Supabase API: http://localhost:54321
- Supabase Studio: http://localhost:54323
- PostgreSQL: localhost:5432

DEV_SETUP.md

@@ -0,0 +1,335 @@
+# Pantry - Local Development Setup
+
+Self-hosted household pantry management app with barcode scanning.
+
+## 🚀 Quick Start
+
+### Prerequisites
+
+- **Docker** & **Docker Compose** (for Supabase backend)
+- **Bun** (for Nuxt frontend) - Install: `curl -fsSL https://bun.sh/install | bash`
+- **Git**
+
+### 1. Clone & Setup
+
+```bash
+git clone https://gitea.jeanlucmakiola.de/pantry-app/pantry.git
+cd pantry
+```
+
+### 2. Start Supabase (Backend)
+
+```bash
+# Start all Supabase services
+docker-compose up -d
+
+# Wait ~10 seconds for services to initialize
+# Check status
+docker-compose ps
+```
+
+**Services running:**
+- PostgreSQL: `localhost:5432`
+- Supabase API: `http://localhost:54321`
+- Supabase Studio: `http://localhost:54323` (admin UI)
+
+### 3. Apply Database Migrations
+
+The migrations are automatically applied on first startup via `/docker-entrypoint-initdb.d`.
+
+To verify:
+```bash
+docker-compose exec db psql -U postgres -d postgres -c "\dt"
+```
+
+You should see: `inventory_items`, `products`, `tags`, `units`, `item_tags`
+
+### 4. Start Nuxt App (Frontend)
+
+```bash
+cd app
+bun install
+bun run dev
+```
+
+**App running:** `http://localhost:3000`
+
+### 5. Open & Test
+
+1. Visit `http://localhost:3000`
+2. Click "Add Manually" to create your first inventory item
+3. Access Supabase Studio at `http://localhost:54323` to view database
+
+---
+
+## 📁 Project Structure
+
+```
+pantry/
+├── app/                    # Nuxt 4 frontend
+│   ├── components/         # Vue components
+│   │   └── inventory/      # Inventory CRUD UI
+│   ├── composables/        # Supabase client, data hooks
+│   ├── pages/              # Routes (index, scan, settings)
+│   └── types/              # TypeScript definitions
+├── supabase/
+│   └── migrations/         # SQL schema & seed data
+├── docker/
+│   └── kong.yml            # API gateway config
+├── docker-compose.yml      # Supabase services
+└── .env                    # Environment variables
+```
+
+---
+
+## 🔧 Common Tasks
+
+### View Logs
+
+```bash
+# All services
+docker-compose logs -f
+
+# Specific service
+docker-compose logs -f db
+docker-compose logs -f auth
+```
+
+### Reset Database
+
+```bash
+# Stop services
+docker-compose down -v
+
+# Restart (migrations auto-apply)
+docker-compose up -d
+```
+
+### Access Database
+
+```bash
+# psql
+docker-compose exec db psql -U postgres -d postgres
+
+# Supabase Studio (GUI)
+# http://localhost:54323
+```
+
+### Run Migrations Manually
+
+```bash
+# If you add new migrations after initial setup
+docker-compose exec db psql -U postgres -d postgres -f /docker-entrypoint-initdb.d/003_helper_functions.sql
+```
+
+### Create Test User
+
+```bash
+# Via Supabase Studio: http://localhost:54323
+# → Authentication → Add User
+# Email: test@example.com
+# Password: password123
+
+# Or via curl:
+curl http://localhost:54321/auth/v1/signup \
+  -H "apikey: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9..." \
+  -H "Content-Type: application/json" \
+  -d '{"email":"test@example.com","password":"password123"}'
+```
+
+---
+
+## 🧪 Testing Features
+
+### 1. Inventory Management
+- Add items manually via form
+- Edit quantities with +/- buttons
+- Delete items
+- View expiry warnings
+
+### 2. Tags & Organization
+- Pre-seeded tags: Fridge, Freezer, Pantry, Dairy, Vegan, etc.
+- Multi-select tags when adding items
+- Color-coded badges
+
+### 3. Units
+- 30 pre-seeded units (g, kg, L, cups, pieces, etc.)
+- Automatic conversion support
+
+### 4. Barcode Scanning (Week 3 - In Progress)
+- Camera access (requires HTTPS in production)
+- Manual barcode entry fallback
+
+---
+
+## 🐛 Troubleshooting
+
+### Port Conflicts
+
+If ports 5432, 54321, or 3000 are in use:
+
+```bash
+# Check what's using the port
+sudo lsof -i :5432
+
+# Option 1: Stop conflicting service
+# Option 2: Change port in docker-compose.yml
+```
+
+### Database Connection Refused
+
+```bash
+# Wait for PostgreSQL to fully start
+docker-compose logs db | grep "ready to accept connections"
+
+# If stuck, restart
+docker-compose restart db
+```
+
+### Migrations Not Applied
+
+```bash
+# Verify migrations directory is mounted
+docker-compose exec db ls -la /docker-entrypoint-initdb.d
+
+# Manually apply
+docker-compose exec db bash
+cd /docker-entrypoint-initdb.d
+for f in *.sql; do psql -U postgres -d postgres -f "$f"; done
+```
+
+### Frontend: Module Not Found
+
+```bash
+cd app
+rm -rf node_modules bun.lock .nuxt
+bun install
+bun run dev
+```
+
+---
+
+## 📊 Database Schema
+
+### Tables
+
+| Table | Purpose | Rows (Est.) |
+|-------|---------|-------------|
+| `inventory_items` | Current inventory | 100-500 |
+| `products` | Barcode cache (Open Food Facts) | 500-2000 |
+| `tags` | Organization labels | 50 (33 pre-seeded) |
+| `units` | Measurement units | 50 (30 pre-seeded) |
+| `item_tags` | Many-to-many item ↔ tag | 200-1000 |
+
+### Pre-Seeded Data
+
+**Units (30):**
+- Weight: g, kg, mg, lb, oz
+- Volume: mL, L, cup, tbsp, tsp, gal, qt, pt
+- Count: piece, dozen, package, bottle, can, jar, box, bag
+
+**Tags (33):**
+- Position: Fridge, Freezer, Pantry, Cabinet
+- Type: Dairy, Meat, Vegetables, Fruits, Snacks
+- Dietary: Vegan, Gluten-Free, Organic, Kosher, Halal
+- Custom: Low Stock, To Buy, Meal Prep, Leftovers
+
+---
+
+## 🔐 Authentication
+
+**Default Setup (Development):**
+- Auto-confirm emails (no SMTP needed)
+- Anyone can sign up
+- JWT tokens valid for 1 hour
+
+**Create Admin User:**
+
+```sql
+-- Via psql
+docker-compose exec db psql -U postgres -d postgres
+
+INSERT INTO auth.users (id, email, encrypted_password, email_confirmed_at)
+VALUES (
+  gen_random_uuid(),
+  'admin@pantry.local',
+  crypt('admin123', gen_salt('bf')),
+  NOW()
+);
+```
+
+---
+
+## 🌐 Environment Variables
+
+**.env** (root)
+```bash
+POSTGRES_PASSWORD=postgres
+JWT_SECRET=your-secret-here
+ANON_KEY=<supabase-anon-key>
+SERVICE_ROLE_KEY=<supabase-service-role-key>
+```
+
+**app/.env** (Nuxt)
+```bash
+NUXT_PUBLIC_SUPABASE_URL=http://localhost:54321
+NUXT_PUBLIC_SUPABASE_ANON_KEY=<same-as-above>
+```
+
+---
+
+## 📈 Development Workflow
+
+1. **Make changes** to Nuxt app → Hot reload at `localhost:3000`
+2. **Database changes** → Create new migration in `supabase/migrations/`
+3. **Test** → Add items, scan barcodes, check database
+4. **Commit** → Feature branch → PR to `develop`
+
+---
+
+## 🚢 Production Deployment (Coming Soon)
+
+See `docs/DEPLOYMENT.md` for:
+- Coolify setup
+- Environment configuration
+- SSL/HTTPS setup
+- Backups
+
+---
+
+## 📚 Documentation
+
+- [Architecture](docs/ARCHITECTURE.md)
+- [Database Schema](docs/DATABASE.md)
+- [API Reference](docs/API.md)
+- [Development Guide](docs/DEVELOPMENT.md)
+
+---
+
+## 🤝 Contributing
+
+This is a personal project, but issues and PRs welcome!
+
+1. Fork the repo
+2. Create feature branch (`git checkout -b feature/amazing-feature`)
+3. Commit changes (`git commit -m 'Add amazing feature'`)
+4. Push to branch (`git push origin feature/amazing-feature`)
+5. Open Pull Request
+
+---
+
+## 📝 License
+
+MIT License - See LICENSE file
+
+---
+
+## 🙋 Support
+
+- Issues: https://gitea.jeanlucmakiola.de/pantry-app/pantry/issues
+- Docs: https://gitea.jeanlucmakiola.de/pantry-app/pantry/wiki
+
+---
+
+**Version:** 0.1.0-alpha (MVP in progress)  
+**Status:** Week 2 complete, Week 3 in progress (14/34 issues done)