Fix orphan references after shitcoin nuke (build round 2)

Stragglers that weren't in any agent's batch but referenced the removed
identifiers:

- tool/configure.dart: stripped 'backupSeeds(Box<HavenSeedStore>)'
  abstract method from generateWownero's emitted template + the
  haven_seed_store.dart import. CI regenerates lib/wownero/wownero.dart
  from this template each build, so the previous lib/wownero/wownero.dart
  cleanup got reverted on rebuild. This is the actual fix.
- lib/core/trade_monitor.dart + lib/view_model/trade_details_view_model.dart:
  removed JupiterExchangeProvider import + ExchangeProviderDescription.jupiter
  switch cases (provider + URL builder).
- lib/src/screens/dashboard/dashboard_page.dart: deleted _showHavenPopup
  helper + its call site + the haven_wallet_removal_popup import.
- lib/src/widgets/haven_wallet_removal_popup.dart: deleted (no callers).
- lib/src/screens/dashboard/pages/balance/crypto_balance_widget.dart:
  removed the zcash 'missing funds' InfoCard and the decred 'syncing'
  InfoCard widgets, plus their _dismissZcash and _rescanInternalChangeZcash
  handlers.
- lib/src/screens/settings/connection_sync_page.dart: removed the TronGrid
  history toggle row.
- lib/src/widgets/bottom_sheet/payment_confirmation_bottom_sheet.dart:
  _isTokenSelectionFlow now only checks evmNetworkSelection (was also
  branching on solana/tronTokenSelection enum values that no longer exist).

Generated .g.dart files for dashboard_view_model and connection_sync_view_model
still reference removed methods (rescanInternalChangeZcash, dismissZcash,
canUseTronGrid, setUseTronGrid). Those will be regenerated by build_runner
on next CI run and the methods will fall out — no manual fix needed.

lib/src/screens/settings/connection_sync_page.dart

@@ -110,14 +110,6 @@ class ConnectionSyncPage extends BasePage {
                                 onChanged: (val) {
                                   _connectionSyncViewModel.setUseBscScan(val);
                                 }),
-                          if (_connectionSyncViewModel.canUseTronGrid)
-                            ListItemToggle(
-                                keyValue: "can_use_trongrid",
-                                label: S.of(context).trongrid_history,
-                                value: _connectionSyncViewModel.useTronGrid,
-                                onChanged: (val) {
-                                  _connectionSyncViewModel.setUseTronGrid(val);
-                                }),
                           if (_connectionSyncViewModel.canUseMempoolFeeAPI)
                             ListItemToggle(
                                 keyValue: "enable_mempool_api",