feat: sync thread grid during idle scaling, skip lock screen while pool mining, add paste preview to import key dialog

- Mining tab: sync s_selected_threads with actual thread count when idle
  thread scaling adjusts threads (solo via genproclimit, pool via
  threads_active), skipping sync during user drag
- Auto-lock: bypass lock screen overlay when xmrig pool mining is active
  so the mining UI remains accessible
- Import key dialog: add clipboard hover preview with transparent overlay
  on the input field, inline key type validation next to title (matching
  send tab paste button pattern), configurable via ui.toml

src/ui/windows/mining_tab.cpp

@@ -140,6 +140,15 @@ void RenderMiningTab(App* app)
         s_threads_initialized = true;
     }
 
+    // Sync thread grid with actual count when idle thread scaling adjusts threads
+    if (app->settings()->getMineWhenIdle() && app->settings()->getIdleThreadScaling() && !s_drag_active) {
+        if (s_pool_mode && state.pool_mining.xmrig_running && state.pool_mining.threads_active > 0) {
+            s_selected_threads = std::min(state.pool_mining.threads_active, max_threads);
+        } else if (mining.generate && mining.genproclimit > 0) {
+            s_selected_threads = std::min(mining.genproclimit, max_threads);
+        }
+    }
+
     ImDrawList* dl = ImGui::GetWindowDrawList();
     GlassPanelSpec glassSpec;
     glassSpec.rounding = Layout::glassRounding();