fix: cashu token amount parsing from proof values

utils/CashuUtils.test.ts

@@ -265,6 +265,16 @@ describe('CashuUtils', () => {
             ).toBe(7);
         });
 
+        it('sums string proof amounts as numbers', () => {
+            expect(
+                CashuUtils.sumProofsValue([
+                    { amount: '64' },
+                    { amount: '32' },
+                    { amount: '4' }
+                ])
+            ).toBe(100);
+        });
+
         it('returns 0 for empty/null', () => {
             expect(CashuUtils.sumProofsValue([])).toBe(0);
             expect(CashuUtils.sumProofsValue(null)).toBe(0);

utils/CashuUtils.ts

@@ -139,7 +139,8 @@ class CashuUtils {
             return 0;
         }
         return proofs.reduce((r: number, c: any) => {
-            return r + c.amount;
+            const amount = Number(c?.amount) || 0;
+            return r + amount;
         }, 0);
     };