feat: non-blocking warmup — connect during daemon initialization

Instead of blocking the entire UI with "Activating best chain..." until
the daemon finishes warmup, treat warmup responses as a successful
connection. The wallet now:

- Sets connected=true + warming_up=true when daemon returns RPC -28
- Shows warmup status with block progress in the loading overlay
- Polls getinfo every few seconds to detect warmup completion
- Allows Console, Peers, Settings tabs during warmup
- Shows orange status indicator with warmup message in status bar
- Skips balance/tx/address refresh until warmup completes
- Triggers full data refresh once daemon is ready

Also: fix curl handle/header leak on reconnect, fill in empty
externalDetected error branch, bump version to v1.2.0 in build scripts.

src/rpc/rpc_client.cpp

@@ -73,6 +73,16 @@ bool RPCClient::connect(const std::string& host, const std::string& port,
     impl_->url = "http://" + host + ":" + port + "/";
     VERBOSE_LOGF("Connecting to dragonxd at %s\n", impl_->url.c_str());
 
+    // Clean up previous curl handle/headers to avoid leaks on retries
+    if (impl_->headers) {
+        curl_slist_free_all(impl_->headers);
+        impl_->headers = nullptr;
+    }
+    if (impl_->curl) {
+        curl_easy_cleanup(impl_->curl);
+        impl_->curl = nullptr;
+    }
+
     // Initialize curl handle
     impl_->curl = curl_easy_init();
     if (!impl_->curl) {
@@ -81,7 +91,7 @@ bool RPCClient::connect(const std::string& host, const std::string& port,
     }
 
     // Set up headers - daemon expects text/plain, not application/json
-    impl_->headers = curl_slist_append(impl_->headers, "Content-Type: text/plain");
+    impl_->headers = curl_slist_append(nullptr, "Content-Type: text/plain");
     std::string auth_header = "Authorization: Basic " + auth_;
     impl_->headers = curl_slist_append(impl_->headers, auth_header.c_str());
 
@@ -97,6 +107,8 @@ bool RPCClient::connect(const std::string& host, const std::string& port,
         json result = call("getinfo");
         if (result.contains("version")) {
             connected_ = true;
+            warming_up_ = false;
+            warmup_status_.clear();
             last_connect_error_.clear();
             DEBUG_LOGF("Connected to dragonxd v%d\n", result["version"].get<int>());
             return true;
@@ -104,7 +116,9 @@ bool RPCClient::connect(const std::string& host, const std::string& port,
     } catch (const std::exception& e) {
         last_connect_error_ = e.what();
         // Daemon warmup messages (Loading block index, Verifying blocks, etc.)
-        // are normal startup progress — don't label them "Connection failed".
+        // are normal startup progress — the daemon is reachable and auth works,
+        // it just hasn't finished initializing yet.  Mark as connected+warmup
+        // so the wallet can show the UI instead of a blocking overlay.
         std::string msg = e.what();
         bool isWarmup = (msg.find("Loading") != std::string::npos ||
                          msg.find("Verifying") != std::string::npos ||
@@ -113,13 +127,19 @@ bool RPCClient::connect(const std::string& host, const std::string& port,
                          msg.find("Rescanning") != std::string::npos ||
                          msg.find("Pruning") != std::string::npos);
         if (isWarmup) {
-            DEBUG_LOGF("Daemon starting: %s\n", msg.c_str());
+            connected_ = true;
+            warming_up_ = true;
+            warmup_status_ = msg;
+            DEBUG_LOGF("Daemon warming up: %s\n", msg.c_str());
+            return true;
         } else {
             DEBUG_LOGF("Connection failed: %s\n", msg.c_str());
         }
     }
 
     connected_ = false;
+    warming_up_ = false;
+    warmup_status_.clear();
     return false;
 }
 
@@ -127,6 +147,8 @@ void RPCClient::disconnect()
 {
     std::lock_guard<std::recursive_mutex> lk(curl_mutex_);
     connected_ = false;
+    warming_up_ = false;
+    warmup_status_.clear();
     if (impl_->curl) {
         curl_easy_cleanup(impl_->curl);
         impl_->curl = nullptr;

src/rpc/rpc_client.h

@@ -53,6 +53,19 @@ public:
      */
     bool isConnected() const { return connected_; }
 
+    /**
+     * @brief True if the last connect() succeeded but daemon returned a warmup error.
+     * The curl handle is valid and auth succeeded — RPC calls will throw warmup errors
+     * until the daemon finishes initializing.
+     */
+    bool isWarmingUp() const { return warming_up_; }
+
+    /**
+     * @brief The warmup status message (e.g. "Activating best chain...").
+     * Empty when not in warmup.
+     */
+    const std::string& getWarmupStatus() const { return warmup_status_; }
+
     /**
      * @brief Get the error message from the last failed connect() attempt.
      */
@@ -182,6 +195,8 @@ private:
     std::string port_;
     std::string auth_;  // Base64 encoded "user:password"
     bool connected_ = false;
+    bool warming_up_ = false;
+    std::string warmup_status_;
     std::string last_connect_error_;
     mutable std::recursive_mutex curl_mutex_;  // serializes all curl handle access