Remodel threading to use a global thread pool so it never block on the main thread. Bump emscripten to 3.1.65

src/CommonModel.h

@@ -2,17 +2,12 @@
 #include "Util.h"
 
 #include <vosk_api.h>
-extern void free(void*);
 struct CommonModel {
   bool normalMdl;
-  std::atomic_bool thrdUsed{};
   int index;
-  std::thread t;
-  std::function<void()> recognizerMain;
   std::string storepath;
   std::string id;
   std::variant<VoskModel*, VoskSpkModel*> mdl;
-
   void extractAndLoad(unsigned char* tarStart, int tarSize);
   int findWord(std::string word);
   CommonModel(int index, bool normalMdl, std::string storepath, std::string id, int tarStart, int tarSize);