Add noexcept qualifications on the plugin side

See the last few commits.

src/plugin/bridges/vst2.h

@@ -52,7 +52,7 @@ class Vst2PluginBridge : PluginBridge<Vst2Sockets<std::jthread>> {
      * Terminate the Wine plugin host process and drop all work when the module
      * gets unloaded.
      */
-    ~Vst2PluginBridge();
+    ~Vst2PluginBridge() noexcept override;
 
     // The four below functions are the handlers from the VST2 API. They are
     // called through proxy functions in `plugin.cpp`.