Phase 1: Project scaffolding and infrastructure

- Scaffold Budget.Api (ASP.NET Core Web API, net10.0) with EF Core + Npgsql
- Scaffold Budget.Client (Vite + React + TypeScript) with /api proxy to localhost:5000
- Define all entity models: Budget, Income, Outgo, KnownUser, BudgetShare
- Configure AppDbContext with EF mappings and cascade deletes
- Add InitialCreate migration
- Configure SPA static file serving + fallback in Program.cs
- Add Dockerfile (multi-stage: node + dotnet sdk + aspnet runtime)
- Add .env.example with all required environment variables

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/Budget.Api/appsettings.json

@@ -0,0 +1,12 @@
+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft.AspNetCore": "Warning"
+    }
+  },
+  "AllowedHosts": "*",
+  "ConnectionStrings": {
+    "DefaultConnection": ""
+  }
+}