feat(lite): lite wallet foundation (inherited working-tree state)

Preserve the previously-uncommitted lite wallet implementation and related dev WIP
under version control:
- src/wallet/ lite services: client bridge, bridge runtime, connection, lifecycle,
  sync, gateway, result parsers, state mapper, artifact contract/resolver, refresh
  services, UI adapters, wallet_backend/capabilities. (Includes two small M1 fixes:
  lifecycle walletReady now parses the response; default chain name -> "main".)
- src/chat/ chat protocol; tests/fixtures/ (lite + hushchat); tools/hushchat_fixture_check.cpp;
  scripts/build-lite-backend-artifact.sh.
- Pre-existing modified app_network/security/wizard, network_refresh_service, sidebar,
  mining_tab, bootstrap dialog, and version headers captured as-is.

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

src/wallet/lite_client_bridge.h

@@ -0,0 +1,84 @@
+// DragonX Wallet - ImGui Edition
+// Copyright 2024-2026 The Hush Developers
+// Released under the GPLv3
+
+#pragma once
+
+#include <string>
+
+namespace dragonx {
+namespace wallet {
+
+struct LiteBridgeStringResult {
+    bool ok = false;
+    std::string value;
+    std::string error;
+};
+
+struct LiteClientBridgeApi {
+    using WalletExistsFn = bool (*)(const char* chainName);
+    using InitializeNewFn = char* (*)(bool dangerous, const char* server);
+    using InitializeNewFromPhraseFn = char* (*)(bool dangerous,
+                                                const char* server,
+                                                const char* seed,
+                                                unsigned long long birthday,
+                                                unsigned long long account,
+                                                bool overwrite);
+    using InitializeExistingFn = char* (*)(bool dangerous, const char* server);
+    using ExecuteFn = char* (*)(const char* command, const char* args);
+    using FreeStringFn = void (*)(char* value);
+    using CheckServerOnlineFn = bool (*)(const char* server);
+    using ShutdownFn = void (*)();
+
+    WalletExistsFn walletExists = nullptr;
+    InitializeNewFn initializeNew = nullptr;
+    InitializeNewFromPhraseFn initializeNewFromPhrase = nullptr;
+    InitializeExistingFn initializeExisting = nullptr;
+    ExecuteFn execute = nullptr;
+    FreeStringFn freeString = nullptr;
+    CheckServerOnlineFn checkServerOnline = nullptr;
+    ShutdownFn shutdown = nullptr;
+};
+
+class LiteClientBridge {
+public:
+    static LiteClientBridge unavailable(std::string reason);
+    static LiteClientBridge fromApi(LiteClientBridgeApi api);
+    static LiteClientBridge linkedSdxl();
+
+    LiteClientBridge(const LiteClientBridge&) = delete;
+    LiteClientBridge& operator=(const LiteClientBridge&) = delete;
+    LiteClientBridge(LiteClientBridge&& other) noexcept;
+    LiteClientBridge& operator=(LiteClientBridge&& other) noexcept;
+    ~LiteClientBridge();
+
+    bool available() const;
+    const std::string& unavailableReason() const { return unavailableReason_; }
+
+    bool walletExists(const std::string& chainName) const;
+    bool checkServerOnline(const std::string& server) const;
+
+    LiteBridgeStringResult initializeNew(bool dangerous, const std::string& server);
+    LiteBridgeStringResult initializeNewFromPhrase(bool dangerous,
+                                                   const std::string& server,
+                                                   const std::string& seed,
+                                                   unsigned long long birthday,
+                                                   unsigned long long account,
+                                                   bool overwrite);
+    LiteBridgeStringResult initializeExisting(bool dangerous, const std::string& server);
+    LiteBridgeStringResult execute(const std::string& command, const std::string& args);
+    void shutdown();
+
+private:
+    LiteClientBridge(LiteClientBridgeApi api, std::string unavailableReason);
+
+    LiteBridgeStringResult unavailableResult() const;
+    LiteBridgeStringResult takeOwnedString(char* rawValue) const;
+
+    LiteClientBridgeApi api_;
+    std::string unavailableReason_;
+    bool shutdownCalled_ = false;
+};
+
+} // namespace wallet
+} // namespace dragonx