Merge branch 'dev' into agent/dex/CUB-39-filament-usage-sync

backend/Program.cs

@@ -52,6 +52,9 @@ builder.Services.AddSwaggerGen(c =>
 // ── QR Code Generation ──────────────────────────────────────
 builder.Services.AddSingleton<IQrCodeService, QrCodeService>();
 
+// ── Cost Per Print Calculation ─────────────────────────────
+builder.Services.AddScoped<ICostPerPrintService, CostPerPrintService>();
+
 // ── FluentValidation ──────────────────────────────────────
 // Registers all validators from the API assembly into DI.
 builder.Services.AddValidatorsFromAssembly(Assembly.GetExecutingAssembly());