daemon version check, idle mining control, bootstrap mirror, import key paste, and cleanup

- Add startup binary version checking for dragonxd/xmrig
- Display daemon version in UI
- Add idle mining thread count adjustment
- Add bootstrap mirror option (bootstrap2.dragonx.is) in setup wizard
- Add paste button to import private key dialog with address validation
- Add z-address generation UI feedback (loading indicator)
- Add option to delete blockchain data while preserving wallet.dat
- Add font scale slider hotkey tooltip (Ctrl+Plus/Ctrl+Minus)
- Fix Windows RPC auth: trim \r from config values, add .cookie fallback
- Fix connection status message during block index loading
- Improve application shutdown to prevent lingering background process

src/config/settings.h

@@ -214,6 +214,14 @@ public:
     int getMineIdleDelay() const { return mine_idle_delay_; }
     void setMineIdleDelay(int seconds) { mine_idle_delay_ = std::max(30, seconds); }
 
+    // Idle thread scaling — scale thread count instead of start/stop
+    bool getIdleThreadScaling() const { return idle_thread_scaling_; }
+    void setIdleThreadScaling(bool v) { idle_thread_scaling_ = v; }
+    int getIdleThreadsActive() const { return idle_threads_active_; }
+    void setIdleThreadsActive(int v) { idle_threads_active_ = std::max(0, v); }
+    int getIdleThreadsIdle() const { return idle_threads_idle_; }
+    void setIdleThreadsIdle(int v) { idle_threads_idle_ = std::max(0, v); }
+
     // Saved pool URLs (user-managed favorites dropdown)
     const std::vector<std::string>& getSavedPoolUrls() const { return saved_pool_urls_; }
     void addSavedPoolUrl(const std::string& url) {
@@ -248,6 +256,10 @@ public:
     int getWindowHeight() const { return window_height_; }
     void setWindowSize(int w, int h) { window_width_ = w; window_height_ = h; }
 
+    // Returns true once after an upgrade (version mismatch detected on load)
+    bool needsUpgradeSave() const { return needs_upgrade_save_; }
+    void clearUpgradeSave() { needs_upgrade_save_ = false; }
+
 private:
     std::string settings_path_;
 
@@ -290,13 +302,16 @@ private:
     // Pool mining
     std::string pool_url_       = "pool.dragonx.is:3433";
     std::string pool_algo_      = "rx/hush";
-    std::string pool_worker_    = "x";
+    std::string pool_worker_    = "";
     int         pool_threads_   = 0;
     bool        pool_tls_       = false;
     bool        pool_hugepages_ = true;
     bool        pool_mode_      = false;   // false=solo, true=pool
     bool        mine_when_idle_ = false;   // auto-start mining when system idle
     int         mine_idle_delay_= 120;     // seconds of idle before mining starts
+    bool        idle_thread_scaling_ = false; // scale threads instead of start/stop
+    int         idle_threads_active_ = 0;    // threads when user active (0 = auto)
+    int         idle_threads_idle_   = 0;    // threads when idle (0 = auto = all)
     std::vector<std::string> saved_pool_urls_; // user-saved pool URL favorites
     std::vector<std::string> saved_pool_workers_; // user-saved worker address favorites
 
@@ -306,6 +321,10 @@ private:
     // Window size (logical pixels at 1x scale; 0 = use default 1200×775)
     int         window_width_   = 0;
     int         window_height_  = 0;
+
+    // Wallet version that last wrote this settings file (for upgrade detection)
+    std::string settings_version_;
+    bool        needs_upgrade_save_ = false;  // true when version changed
 };
 
 } // namespace config