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>

tests/fake_lite_backend.h

@@ -58,8 +58,12 @@ inline char* liteFakeInitFromPhrase(bool, const char*, const char*,
     return liteFakeDup("{\"result\":\"restored\"}");
 }
 inline char* liteFakeInitExisting(bool, const char*) { return liteFakeDup("{\"result\":\"opened\"}"); }
-inline char* liteFakeExecute(const char* command, const char*)
+inline char* liteFakeExecute(const char* command, const char* args)
 {
+    // new-address generation returns a JSON array with the new address (type from args: zs/R).
+    if (command && std::strcmp(command, "new") == 0) {
+        return liteFakeDup(args && std::strcmp(args, "R") == 0 ? "[\"R1fakenew\"]" : "[\"zs1fakenew\"]");
+    }
     // A command named "boom" yields an "Error:"-prefixed response (the bridge's
     // looksLikeError contract maps that to ok=false).
     if (command && std::strcmp(command, "boom") == 0) {