Don't fail when user is not authenticated, and public budgets are missing

src/routes/budget/+server.ts

@@ -68,14 +68,23 @@ export const POST: RequestHandler = async ({ fetch, locals, request }) => {
       result: (await fs.readJson(cachePath)).budgetSimulation,
       hash: cacheDigest,
       isPublic: isSimulationPublic,
-    } as BudgetSimulation)
-  } else if (user === undefined && (await fs.pathExists(baseCachePath))) {
+    })
+  } else if (user === undefined) {
+    if (await fs.pathExists(baseCachePath)) {
       return json({
         errors: [],
         result: (await fs.readJson(baseCachePath)).budgetSimulation,
         hash: cacheDigest,
         isPublic: true,
-    } as BudgetSimulation)
+      })
+    } else {
+      return json({
+        errors: ["Utilisateur anonyme et calcul budgétaire non pré-calculé"],
+        // result: undefined,
+        hash: cacheDigest,
+        isPublic: true,
+      })
+    }
   }
 
   const payload = {