feat(lite): M2b-1/2 — shared-bridge refactor + sync/refresh into WalletState

Shared-bridge refactor (litelib is a global singleton; every LiteClientBridge calls
litelib_shutdown() on destruction, so services must not each own one):
- LiteWalletLifecycleService, LiteWalletGateway, LiteSyncService now take a non-owning
  LiteClientBridge*; LiteWalletController owns the single bridge and passes &bridge_.

Sync + controller refresh:
- LiteSyncService::startSync executes the real "sync" command (was a stub).
- LiteWalletController: startSync() (auto-fires when a wallet becomes ready) and
  refreshWalletState(WalletState&) — polls syncstatus, runs gateway.refresh(), maps the
  bundle, applies balances/addresses/transactions/sync into WalletState.

Tests:
- fake_lite_backend.h returns command-shaped JSON (per tests/fixtures/lite/result_parsers.json).
- testLiteWalletControllerRefreshPopulatesState drives the full path against the fake.
- Surfaced + worked around a real integration issue: parseLiteInfoResponse requires
  latest_block_height and the gateway aborts the whole refresh on the first command's
  parse failure (fragile vs partial backend responses; hardening tracked for M2b-3).

Verified: ctest green; lite+backend, full-node, lite-no-backend apps + lite_smoke build clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/wallet/lite_wallet_gateway.cpp

@@ -135,11 +135,11 @@ LiteWalletRefreshBundle assembleLiteWalletRefreshBundle(const std::vector<LiteWa
 
 LiteWalletGateway::LiteWalletGateway(WalletCapabilities capabilities,
                                      LiteConnectionSettings connectionSettings,
-                                     LiteClientBridge bridge,
+                                     LiteClientBridge* bridge,
                                      LiteWalletGatewayOptions options)
     : capabilities_(capabilities),
       connectionSettings_(std::move(connectionSettings)),
-      bridge_(std::move(bridge)),
+      bridge_(bridge),
       options_(options)
 {
 }
@@ -148,7 +148,7 @@ LiteWalletGatewayAvailability LiteWalletGateway::availability() const
 {
     if (!isLiteBuild(capabilities_)) return LiteWalletGatewayAvailability::UnsupportedBuild;
     if (!supportsLiteBackend(capabilities_)) return LiteWalletGatewayAvailability::BackendUnavailable;
-    if (!bridge_.available()) return LiteWalletGatewayAvailability::BridgeUnavailable;
+    if (!bridge_ || !bridge_->available()) return LiteWalletGatewayAvailability::BridgeUnavailable;
     if (!selectLiteServer(connectionSettings_).ok) return LiteWalletGatewayAvailability::NoUsableServer;
     if (!options_.allowBridgeCalls) return LiteWalletGatewayAvailability::BridgeCallsDisabled;
     return LiteWalletGatewayAvailability::Ready;
@@ -288,7 +288,7 @@ WalletBackendStatus LiteWalletGateway::statusFor(LiteWalletGatewayAvailability a
         case LiteWalletGatewayAvailability::BridgeUnavailable:
             return makeGatewayStatus(
                 WalletBackendState::Unavailable,
-                detail.empty() ? bridge_.unavailableReason() : detail);
+                detail.empty() ? (bridge_ ? bridge_->unavailableReason() : "lite bridge is unavailable") : detail);
         case LiteWalletGatewayAvailability::BridgeCallsDisabled:
             return makeGatewayStatus(
                 WalletBackendState::Unavailable,
@@ -319,7 +319,7 @@ LiteWalletGatewayCommandResult LiteWalletGateway::executePlannedCommand(const Li
     result.plan = plan;
     result.attempted = true;
 
-    const auto bridgeCall = bridge_.execute(plan.commandName, plan.args);
+    const auto bridgeCall = bridge_->execute(plan.commandName, plan.args);
     result.bridgeResponseRedacted = bridgeCall.ok || !bridgeCall.error.empty() ? "<redacted>" : "<empty>";
     if (!bridgeCall.ok) {
         result.status = makeGatewayStatus(WalletBackendState::Error, "lite wallet gateway bridge call failed");