fix(lite): rebuild controller on lite-server change (stale-settings audit HIGH)

The LiteWalletController was constructed once at App::init() with the lite
connection settings known at startup; changing the lite server in Settings
persisted to disk but never reached the live controller, so the new server had
no effect until the next launch.

Factor the construction into App::rebuildLiteWallet() and call it after a
successful server-selection save. The rebuild deliberately preserves a live
session: if a wallet is already open (and possibly mid-sync), it no-ops and the
new selection applies on the next controller build, rather than discarding the
open wallet and its uninterruptible in-flight sync.

Closes the last remaining HIGH from the session audit.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app.cpp

@@ -169,12 +169,7 @@ bool App::init()
     // Lite builds with a linked SDXL backend own a lite wallet controller that drives
     // real create/open/restore through the bridge. Full-node and unlinked-lite builds
     // leave lite_wallet_ null (the UI falls back to validation-only).
-    if (supportsLiteBackend()) {
-        lite_wallet_ = wallet::LiteWalletController::createLinked(
-            walletCapabilities(),
-            wallet::liteConnectionSettingsFromAppSettings(*settings_));
-        lite_wallet_->setPersistCallback([this]() { settings_->save(); });
-    }
+    rebuildLiteWallet();
 
     // Apply verbose logging preference from saved settings
     util::Logger::instance().setVerbose(settings_->getVerboseLogging());
@@ -370,6 +365,21 @@ void App::preFrame()
     }
 }
 
+void App::rebuildLiteWallet()
+{
+    if (!supportsLiteBackend() || !settings_) return;
+    // Don't tear down a live session: if a wallet is already open (and possibly mid-sync), the
+    // new server selection is already persisted to settings and will take effect the next time
+    // the controller is built (next launch, or before another wallet is opened). Rebuilding now
+    // would discard the open wallet and its in-flight, uninterruptible sync.
+    if (lite_wallet_ && lite_wallet_->walletOpen()) return;
+
+    lite_wallet_ = wallet::LiteWalletController::createLinked(
+        walletCapabilities(),
+        wallet::liteConnectionSettingsFromAppSettings(*settings_));
+    lite_wallet_->setPersistCallback([this]() { settings_->save(); });
+}
+
 void App::update()
 {
     PERF_SCOPE("Update.Total");

src/app.h

@@ -157,6 +157,9 @@ public:
     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(); }
+    // (Re)build the lite controller from current settings so a changed lite-server selection
+    // takes effect. No-op on non-lite/unlinked builds; preserves a live wallet (see app.cpp).
+    void rebuildLiteWallet();
     WalletState& state() { return state_; }
     const WalletState& state() const { return state_; }
     const WalletState& getWalletState() const { return state_; }

src/ui/pages/settings_page.cpp

@@ -197,6 +197,9 @@ static void saveLiteServerSelectionFromPageState(App* app) {
     const auto result = wallet::executeLiteWalletServerSelectionUi(*app->settings(), input);
     if (result.settingsWritten) {
         s_settingsState.lite_server_status = "Saved";
+        // Rebuild the lite controller so the newly-saved server actually takes effect (it is
+        // otherwise captured once at startup). No-op if a wallet is already open mid-session.
+        app->rebuildLiteWallet();
     } else if (!result.error.empty()) {
         s_settingsState.lite_server_status = result.error;
         Notifications::instance().warning(result.error);