fix(native-chat): match journal commit signature in receipt test (#26788)

The receipt transaction test's fake writer took a single row, but the journal commit hook now receives an array of rows. The mismatch broke typecheck. The mock now accepts the rows array and spreads them into the captured list. The test also asserts the committed row's contents, so a wrong row would fail the test instead of passing on length alone.

src/main/native-chat/agent-session-journal/command-receipt-transaction.test.ts

@@ -114,6 +114,7 @@ describe('command receipt transaction hook', () => {
       buildCommandReceiptTransaction(scope, () => ({ ...receipt, result }))
     )
     expect(committed).toHaveLength(1)
+    expect(committed[0]).toEqual(epochRow(7, 1000))
     expect(storedRows()).toEqual([{ seq: 7 }])
     expect(readReceipt()).toEqual({
       verdict: 'readable',