feat(lite): M3 — new-address generation + sync-indicator confirmation

- LiteWalletController::newAddress(shielded) runs the backend "new" command ("zs"/"R" ->
  do_new_address), parses the ["addr"] response, and returns the new address; the next
  refresh lists it. Fast (local derivation), safe on the UI thread.
- fake_lite_backend returns ["zs1fakenew"]/["R1fakenew"] for "new" by args.
- testLiteWalletControllerNewAddress covers shielded/transparent + no-wallet error.

Also confirmed (no code needed): the sync-progress indicator already works for lite —
balance_tab reads state.sync.* which M2b-3 populates. Per-address balances landed in M2.

Remaining M3 is pure UI wiring (receive_tab button -> newAddress, loading/empty states),
which isn't verifiable without a GUI session.

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

src/wallet/lite_wallet_controller.cpp

@@ -11,6 +11,7 @@
 #include <unordered_map>
 #include <utility>
 
+#include <nlohmann/json.hpp>
 #include <sodium.h>
 
 namespace dragonx {
@@ -202,6 +203,35 @@ std::optional<LiteWalletAppRefreshModel> LiteWalletController::refreshModel()
     return mapped.model;
 }
 
+LiteNewAddressResult LiteWalletController::newAddress(bool shielded)
+{
+    LiteNewAddressResult out;
+    if (!walletOpen_.load() || !bridge_) {
+        out.error = "no wallet is open";
+        return out;
+    }
+    // Backend address-type tokens: "zs" (shielded) / "R" (transparent) (do_new_address).
+    const auto result = bridge_->execute("new", shielded ? "zs" : "R");
+    if (!result.ok) {
+        out.error = result.error.empty() ? "new address generation failed" : result.error;
+        return out;
+    }
+    // Response is a JSON array with the new address, e.g. ["zs1..."].
+    try {
+        const auto parsed = nlohmann::json::parse(result.value);
+        if (parsed.is_array() && !parsed.empty() && parsed[0].is_string()) {
+            out.address = parsed[0].get<std::string>();
+        } else if (parsed.is_string()) {
+            out.address = parsed.get<std::string>();
+        }
+    } catch (...) {
+        // fall through to the error below
+    }
+    out.ok = !out.address.empty();
+    if (!out.ok) out.error = "could not parse new address response";
+    return out;
+}
+
 bool LiteWalletController::refreshWalletState(dragonx::WalletState& state)
 {
     auto model = refreshModel();