Add budget configuration to session interface

src/app.d.ts

@@ -20,6 +20,12 @@ declare namespace App {
       subdomains?: string
       url: string
     }
+    budget: {
+      apiBudgetUrl: string
+      apiBudgetEndpointName: string
+      calculationBaseYear: number
+      calculationPlfYear: number
+    }
     openfiscaRepository: SessionOpenFiscaRepository
     portalUrl: string
     title: string

src/lib/server/config.ts

@@ -31,7 +31,7 @@ export interface Config {
   title: string
 
   // Budget
-  budget?: {
+  budget: {
     apiBudgetUrl: string
     apiBudgetEndpointName: string
     calculationBaseYear: number