fix(lite): render a lite send as a negative debit, not a green "+"; recover unauthored-send amounts

Lite-parity audit, two History-correctness findings (display/parse only — no send/broadcast call touched):
- A lite send carried a POSITIVE tx.amount, so History, the Details dialog and CSV export rendered an
  outgoing payment as a green "+" receipt (the full node uses a negative debit). The mapper already
  computes signedAmountZatoshis (negative for sends, positive for receives); applyLiteRefreshModelToWalletState
  now uses it for tx.amount, so the shared UI shows a red "-" and CSV a negative value. The summary cards
  use std::abs and are unaffected.
- A send this wallet did not author (seed restore / another device) has empty outgoing_metadata, so the
  parser summed it to 0 and showed amount 0 with a blank address, understating Sent totals. parseTransactionRecord
  now falls back to |record.amount| (the net debit, incl. fee) when the metadata sum is 0, tolerant of a
  missing/odd field; explicit outgoing_metadata still wins.

Tests: testLiteSendAmountIsNegative (send maps to <0, receive stays >0) and
testLiteForeignSendFallsBackToRecordAmount.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/wallet/lite_wallet_controller.cpp

@@ -435,7 +435,9 @@ void applyLiteRefreshModelToWalletState(const LiteWalletAppRefreshModel& model,
             } else {
                 tx.type = record.signedAmountZatoshis < 0 ? "send" : "receive";
             }
-            tx.amount = static_cast<double>(record.amountZatoshis) / kZatoshisPerCoin;
+            // Signed like the full node: a send is a negative debit, a receive positive. Consumers
+            // (History/Details/CSV) pick sign + colour from this; the summary cards use std::abs.
+            tx.amount = static_cast<double>(record.signedAmountZatoshis) / kZatoshisPerCoin;
             tx.timestamp = record.timestamp;
             tx.address = record.address;
             tx.memo = record.memo;