feat(lite): real backend integration — controller, M0-M2a wiring, smoke tool, tests

- LiteWalletController (src/wallet/lite_wallet_controller.*): App-owned; runs real
  create/open/restore via the linked SDXL bridge with allowBridgeCalls=true; wipes
  seed/passphrase with sodium_memzero; persists on a ready wallet. M2a:
  applyLiteRefreshModelToWalletState maps a parsed refresh bundle into WalletState
  (zatoshi->DRGX, z/t split, tx typing + confirmations, sync progress).
- App wiring: liteWallet() accessor + init() construction when supportsLiteBackend();
  persist -> settings save.
- settings_page: "Validate" reroutes to the controller for real execution (validation-
  only fallback otherwise); wipes UI secret buffers after submit.
- chain name default -> "main" with load-time migration of legacy "DRAGONX"
  (settings.cpp), preventing the backend "Unknown chain" panic.
- M0: build.sh --lite-backend flag; lite_smoke real-backend tool + CMake targets;
  tests/fake_lite_backend.h deterministic harness.
- Tests (test_phase4): injectable-fake bridge, controller lifecycle, chain-name
  migration, refresh->WalletState mapping; plus the lite test-suite churn-cleanup rewrite.

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

tools/lite_smoke.cpp

@@ -0,0 +1,67 @@
+// DragonX Wallet - ImGui Edition
+// Copyright 2024-2026 The Hush Developers
+// Released under the GPLv3
+//
+// Real-backend smoke harness for the lite wallet bridge. Links the actual SDXL
+// litelib_* backend (via the same imported CMake target the app uses) and exercises
+// LiteClientBridge against a real lightwalletd server. This is the "real backend smoke
+// test" the implementation plan gates behind passing fake-backend tests.
+//
+//   lite_smoke [server-url] [--create]
+//
+// Read-only by default (available / checkServerOnline / walletExists). Pass --create to
+// also attempt a real litelib_initialize_new (writes wallet state — run with an isolated
+// HOME, e.g. HOME=/tmp/lite_smoke env, so it cannot clobber a real wallet).
+
+#include "wallet/lite_client_bridge.h"
+#include "wallet/lite_connection_service.h"
+
+#include <cstdio>
+#include <string>
+
+int main(int argc, char** argv)
+{
+    using namespace dragonx::wallet;
+
+    std::string server = "https://lite.dragonx.is";
+    bool doCreate = false;
+    for (int i = 1; i < argc; ++i) {
+        const std::string arg = argv[i];
+        if (arg == "--create") doCreate = true;
+        else server = arg;
+    }
+
+    std::printf("[lite-smoke] server      = %s\n", server.c_str());
+
+    auto bridge = LiteClientBridge::linkedSdxl();
+    std::printf("[lite-smoke] available() = %s\n", bridge.available() ? "true" : "false");
+    if (!bridge.available()) {
+        std::printf("[lite-smoke] reason      = %s\n", bridge.unavailableReason().c_str());
+        std::printf("[lite-smoke] FAIL: backend not linked\n");
+        return 2;
+    }
+
+    const bool walletExists = bridge.walletExists(kDragonXLiteChainName);
+    std::printf("[lite-smoke] walletExists(%s) = %s\n", kDragonXLiteChainName, walletExists ? "true" : "false");
+
+    const bool online = bridge.checkServerOnline(server);
+    std::printf("[lite-smoke] checkServerOnline()   = %s\n", online ? "true" : "false");
+
+    if (doCreate) {
+        std::printf("[lite-smoke] initializeNew() ... (real network + writes wallet state)\n");
+        auto result = bridge.initializeNew(false, server);
+        std::printf("[lite-smoke] initializeNew ok = %s\n", result.ok ? "true" : "false");
+        if (result.ok) {
+            // The response is the new wallet's SEED PHRASE — never print it. Report only
+            // that a well-formed, non-empty response came back.
+            std::printf("[lite-smoke]   wallet created; response len = %zu (seed redacted)\n",
+                        result.value.size());
+        } else {
+            std::printf("[lite-smoke]   error = %s\n", result.error.c_str());
+        }
+    }
+
+    bridge.shutdown();
+    std::printf("[lite-smoke] done (real litelib_* symbols are callable; results above are live)\n");
+    return 0;
+}