feat: initial project setup

- Add .NET 8 backend with Clean Architecture
- Add React + Vite + TypeScript frontend
- Implement authentication with JWT
- Implement Azure Blob Storage client
- Implement OCR integration
- Implement supplier matching service
- Implement voucher generation
- Implement Fortnox provider
- Add unit and integration tests
- Add Docker Compose configuration

backend/README.md

@@ -0,0 +1,44 @@
+# Invoice Master - Backend
+
+## Project Structure
+
+This backend follows Clean Architecture with the following projects:
+
+- **InvoiceMaster.Core** - Domain entities, interfaces, value objects
+- **InvoiceMaster.Application** - Business logic, CQRS commands/queries
+- **InvoiceMaster.Infrastructure** - EF Core, repositories, external services
+- **InvoiceMaster.Integrations** - Accounting system providers
+- **InvoiceMaster.API** - Web API entry point
+
+## Getting Started
+
+### Prerequisites
+
+- .NET 8 SDK
+- PostgreSQL 15+
+- Redis 7+ (optional)
+
+### Running Locally
+
+```bash
+# Restore dependencies
+dotnet restore
+
+# Run database migrations
+cd src/InvoiceMaster.Infrastructure
+dotnet ef database update --startup-project ../InvoiceMaster.API
+
+# Run the API
+cd ../InvoiceMaster.API
+dotnet run
+```
+
+### Running Tests
+
+```bash
+dotnet test
+```
+
+## Environment Variables
+
+See `src/InvoiceMaster.API/appsettings.Development.json` for configuration.