fix: Blanko-Build-Fehler (data-Verzeichnis + users-Schema) und publish-win ignorieren

- Program.cs: Directory.CreateDirectory(dataDir) vor DB-Zugriff
- DatabaseService: is_admin, persona, settings, default_path ins CREATE TABLE users
- .gitignore + gott.csproj: publish-win/ ausschließen

Program.cs

@@ -12,6 +12,7 @@ var builder = WebApplication.CreateBuilder(args);
 builder.Services.AddHttpClient();
 
 var dataDir = Path.Combine(AppContext.BaseDirectory, "data");
+Directory.CreateDirectory(dataDir);
 
 var dbPath = Path.Combine(dataDir, "gott.db");
 var authService = new AuthService(dbPath);