feat(wallet): persist history and surface pending sends

Add an encrypted SQLite transaction history cache with cached tip metadata and
per-address shielded scan progress so startup and full refreshes avoid
re-scanning every z-address while still invalidating on wallet/address/rescan
changes.

Improve wallet history loading by paging transparent transactions, preserving
cached shielded and sent rows, keeping recent/unconfirmed activity visible, and
classifying mining-address receives. Show z_sendmany opid sends immediately in
History and Overview, pin pending rows through refreshes, and apply optimistic
address/balance debits until opids resolve.

Add timestamped RPC console tracing by source/method without logging params or
results, reduce redundant refresh/RPC calls, and cache Explorer recent block
summaries in SQLite.

Expand focused tests for transaction cache encryption, scan-progress
persistence/invalidation, history preservation, operation-status parsing,
pending send visibility, and Explorer/RPC refresh behavior.

src/rpc/rpc_client.cpp

@@ -10,13 +10,76 @@
 #include "../util/base64.h"
 
 #include <curl/curl.h>
+#include <atomic>
 #include <cstdio>
 #include <cstring>
+#include <utility>
 #include "../util/logger.h"
 
 namespace dragonx {
 namespace rpc {
 
+namespace {
+
+std::mutex g_trace_mutex;
+RPCClient::TraceCallback g_trace_callback;
+std::atomic_bool g_trace_enabled{false};
+thread_local std::string g_trace_source;
+
+void emitRpcTrace(const std::string& method)
+{
+    if (!g_trace_enabled.load(std::memory_order_relaxed)) return;
+
+    RPCClient::TraceCallback callback;
+    {
+        std::lock_guard<std::mutex> lock(g_trace_mutex);
+        callback = g_trace_callback;
+    }
+    if (!callback) return;
+
+    std::string source = g_trace_source.empty() ? std::string("App") : g_trace_source;
+    callback(source, method);
+}
+
+} // namespace
+
+RPCClient::TraceScope::TraceScope(std::string source)
+    : previous_(RPCClient::currentTraceSource())
+{
+    RPCClient::setTraceSource(std::move(source));
+}
+
+RPCClient::TraceScope::~TraceScope()
+{
+    RPCClient::setTraceSource(std::move(previous_));
+}
+
+void RPCClient::setTraceCallback(TraceCallback callback)
+{
+    std::lock_guard<std::mutex> lock(g_trace_mutex);
+    g_trace_callback = std::move(callback);
+}
+
+void RPCClient::setTraceEnabled(bool enabled)
+{
+    g_trace_enabled.store(enabled, std::memory_order_relaxed);
+}
+
+bool RPCClient::isTraceEnabled()
+{
+    return g_trace_enabled.load(std::memory_order_relaxed);
+}
+
+std::string RPCClient::currentTraceSource()
+{
+    return g_trace_source;
+}
+
+void RPCClient::setTraceSource(std::string source)
+{
+    g_trace_source = std::move(source);
+}
+
 // Callback for libcurl to write response data
 static size_t WriteCallback(void* contents, size_t size, size_t nmemb, std::string* userp) {
     size_t totalSize = size * nmemb;
@@ -71,6 +134,7 @@ bool RPCClient::connect(const std::string& host, const std::string& port,
     std::lock_guard<std::recursive_mutex> lk(curl_mutex_);
     host_ = host;
     port_ = port;
+    last_connect_info_ = json();
 
     // Create Basic auth header with proper base64 encoding
     std::string credentials = user + ":" + password;
@@ -116,6 +180,7 @@ bool RPCClient::connect(const std::string& host, const std::string& port,
             warming_up_ = false;
             warmup_status_.clear();
             last_connect_error_.clear();
+            last_connect_info_ = result;
             DEBUG_LOGF("Connected to dragonxd v%d\n", result["version"].get<int>());
             return true;
         }
@@ -146,15 +211,23 @@ bool RPCClient::connect(const std::string& host, const std::string& port,
     connected_ = false;
     warming_up_ = false;
     warmup_status_.clear();
+    last_connect_info_ = json();
     return false;
 }
 
+json RPCClient::getLastConnectInfo() const
+{
+    std::lock_guard<std::recursive_mutex> lk(curl_mutex_);
+    return last_connect_info_;
+}
+
 void RPCClient::disconnect()
 {
     std::lock_guard<std::recursive_mutex> lk(curl_mutex_);
     connected_ = false;
     warming_up_ = false;
     warmup_status_.clear();
+    last_connect_info_ = json();
     if (impl_->curl) {
         curl_easy_cleanup(impl_->curl);
         impl_->curl = nullptr;
@@ -182,6 +255,8 @@ json RPCClient::call(const std::string& method, const json& params)
         throw std::runtime_error("Not connected");
     }
 
+    emitRpcTrace(method);
+
     json payload = makePayload(method, params);
     std::string body = payload.dump();
     std::string response_data;
@@ -235,6 +310,8 @@ json RPCClient::call(const std::string& method, const json& params, long timeout
         throw std::runtime_error("Not connected");
     }
 
+    emitRpcTrace(method);
+
     // Temporarily override timeout
     long prevTimeout = 30L;
     curl_easy_setopt(impl_->curl, CURLOPT_TIMEOUT, timeoutSec);
@@ -294,6 +371,8 @@ std::string RPCClient::callRaw(const std::string& method, const json& params)
         throw std::runtime_error("Not connected");
     }
 
+    emitRpcTrace(method);
+
     json payload = makePayload(method, params);
     std::string body = payload.dump();
     std::string response_data;