Fix: Move plugin scan to background thread, scan on button click not on editor open

Source/PluginBridgeEditor.h

@@ -16,7 +16,7 @@ public:
 
 private:
     void timerCallback() override;
-    void scanPlugins();
+    void scanAndShowMenu();
     void showPluginMenu();
     void loadPluginByIndex(int index);
 
@@ -28,12 +28,12 @@ private:
     juce::Label portLabel;
     juce::Label pluginLabel;
     juce::TextButton pluginButton{"Select Plugin..."};
-    juce::TextEditor searchBox;
 
-    // Scanned plugins
+    // Scanned plugins (persists across editor open/close via static)
     juce::KnownPluginList knownPlugins;
     juce::AudioPluginFormatManager scanFormatManager;
-    bool hasScanned = false;
+    bool scanComplete = false;
+    bool scanning = false;
 
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR(PluginBridgeEditor)
 };