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>

src/app.h

@@ -19,6 +19,7 @@
 #include "services/wallet_security_controller.h"
 #include "services/wallet_security_workflow.h"
 #include "util/async_task_manager.h"
+#include "wallet/wallet_capabilities.h"
 #include "ui/sidebar.h"
 #include "ui/windows/console_tab.h"
 #include "imgui.h"
@@ -32,6 +33,7 @@ namespace dragonx {
     namespace config { class Settings; }
     namespace daemon { class DaemonController; class EmbeddedDaemon; class XmrigManager; }
     namespace util { class Bootstrap; class SecureVault; }
+    namespace wallet { class LiteWalletController; }
 }
 
 namespace dragonx {
@@ -130,8 +132,13 @@ public:
      * @brief Whether we are in the shutdown phase
      */
     bool isShuttingDown() const { return shutting_down_; }
-    bool isLiteBuild() const { return DRAGONX_LITE_BUILD != 0; }
-    bool supportsEmbeddedDaemon() const { return DRAGONX_ENABLE_EMBEDDED_DAEMON != 0; }
+    wallet::WalletCapabilities walletCapabilities() const { return wallet::currentWalletCapabilities(); }
+    bool isLiteBuild() const { return wallet::isLiteBuild(walletCapabilities()); }
+    bool supportsEmbeddedDaemon() const { return wallet::supportsEmbeddedDaemon(walletCapabilities()); }
+    bool supportsFullNodeLifecycleActions() const { return wallet::supportsFullNodeLifecycleActions(walletCapabilities()); }
+    bool supportsSoloMining() const { return wallet::supportsSoloMining(walletCapabilities()); }
+    bool supportsPoolMining() const { return wallet::supportsPoolMining(walletCapabilities()); }
+    bool supportsLiteBackend() const { return wallet::supportsLiteBackend(walletCapabilities()); }
 
     /**
      * @brief Render the shutdown overlay (called instead of normal UI during shutdown)
@@ -148,6 +155,8 @@ public:
     rpc::RPCClient* rpc() { return rpc_.get(); }
     rpc::RPCWorker* worker() { return worker_.get(); }
     config::Settings* settings() { return settings_.get(); }
+    // Lite wallet controller (non-null only in lite builds with a linked backend).
+    wallet::LiteWalletController* liteWallet() { return lite_wallet_.get(); }
     WalletState& state() { return state_; }
     const WalletState& state() const { return state_; }
     const WalletState& getWalletState() const { return state_; }
@@ -276,8 +285,8 @@ public:
     bool startEmbeddedDaemon();
     void stopEmbeddedDaemon();
     bool isEmbeddedDaemonRunning() const;
-    bool isUsingEmbeddedDaemon() const { return use_embedded_daemon_; }
-    void setUseEmbeddedDaemon(bool use) { use_embedded_daemon_ = use; }
+    bool isUsingEmbeddedDaemon() const { return supportsEmbeddedDaemon() && use_embedded_daemon_; }
+    void setUseEmbeddedDaemon(bool use) { use_embedded_daemon_ = use && supportsEmbeddedDaemon(); }
     void rescanBlockchain();  // restart daemon with -rescan flag
     void deleteBlockchainData();  // stop daemon, delete chain data, restart fresh
     bool stopDaemonForBootstrap(); // stop daemon + disconnect for bootstrap, returns true if was running
@@ -406,6 +415,7 @@ private:
     rpc::ConnectionConfig saved_config_;
 
     std::unique_ptr<config::Settings> settings_;
+    std::unique_ptr<wallet::LiteWalletController> lite_wallet_;  // lite builds w/ linked backend
     std::unique_ptr<daemon::DaemonController> daemon_controller_;
     std::unique_ptr<daemon::XmrigManager> xmrig_manager_;
     util::AsyncTaskManager async_tasks_;
@@ -441,7 +451,7 @@ private:
     bool show_address_book_ = false;
     
     // Embedded daemon state
-    bool use_embedded_daemon_ = (DRAGONX_ENABLE_EMBEDDED_DAEMON != 0);
+    bool use_embedded_daemon_ = wallet::supportsEmbeddedDaemon(wallet::currentWalletCapabilities());
     std::string daemon_status_;
     mutable std::string daemon_mem_diag_;  // diagnostic info for daemon memory detection
     size_t daemon_output_offset_ = 0;      // for incremental output parsing (rescan detection)