fix: show P&L debit/credit totals on journal entries list

The previous aggregation used simple SUM(debit)/SUM(credit) which
always produced equal values for balanced entries. This was misleading
for entries with income/expense lines (e.g., monthly actuals).

Now, when an entry has income/expense lines, the totals reflect only
P&L account activity (expenses as debits, income as credits), excluding
the cash offset. For balance-sheet-only entries (opening balances,
adjustments), the full entry totals are shown.

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

backend/src/modules/journal-entries/journal-entries.service.ts

@@ -13,6 +13,16 @@ export class JournalEntriesService {
   async findAll(filters: { from?: string; to?: string; accountId?: string; type?: string }) {
     let sql = `
       SELECT je.*,
+        CASE
+          WHEN SUM(CASE WHEN a.account_type IN ('income','expense') THEN 1 ELSE 0 END) > 0
+          THEN COALESCE(SUM(CASE WHEN a.account_type IN ('income','expense') THEN jel.debit ELSE 0 END), 0)
+          ELSE COALESCE(SUM(jel.debit), 0)
+        END as total_debit,
+        CASE
+          WHEN SUM(CASE WHEN a.account_type IN ('income','expense') THEN 1 ELSE 0 END) > 0
+          THEN COALESCE(SUM(CASE WHEN a.account_type IN ('income','expense') THEN jel.credit ELSE 0 END), 0)
+          ELSE COALESCE(SUM(jel.credit), 0)
+        END as total_credit,
         json_agg(json_build_object(
           'id', jel.id, 'account_id', jel.account_id,
           'debit', jel.debit, 'credit', jel.credit, 'memo', jel.memo,