fix(webapp): branch and warehouse select not showing saved values in edit mode

Fixed an issue where branch and warehouse select fields were not displaying
saved values when editing existing transactions. The useSetPrimaryBranchToForm
and useSetPrimaryWarehouseToForm hooks were overwriting saved values with
primary defaults on every form load.

Changes:
- Added isNewMode check to useSetPrimaryBranchToForm hook
- Added isNewMode check to useSetPrimaryWarehouseToForm hook
- Updated InvoiceFormProvider to expose isNewMode in context

Affected forms:
- Sales: Invoice, Estimate, Receipt, CreditNote, PaymentReceived
- Purchases: Bill, VendorCredit, PaymentMade
- Expense
- MakeJournal (Manual Journal)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/webapp/src/containers/Accounting/MakeJournal/utils.tsx

@@ -213,17 +213,17 @@ export const currenciesFieldShouldUpdate = (newProps, oldProps) => {
 
 export const useSetPrimaryBranchToForm = () => {
   const { setFieldValue } = useFormikContext();
-  const { branches, isBranchesSuccess } = useMakeJournalFormContext();
+  const { branches, isBranchesSuccess, isNewMode } = useMakeJournalFormContext();
 
   React.useEffect(() => {
-    if (isBranchesSuccess) {
+    if (isBranchesSuccess && isNewMode) {
       const primaryBranch = branches.find((b) => b.primary) || first(branches);
 
       if (primaryBranch) {
         setFieldValue('branch_id', primaryBranch.id);
       }
     }
-  }, [isBranchesSuccess, setFieldValue, branches]);
+  }, [isBranchesSuccess, setFieldValue, branches, isNewMode]);
 };
 
 export const useManualJournalCreditTotal = () => {