Make isviewer a sink to file

src/backend/core/Mem.cpp

@@ -9,6 +9,7 @@ namespace n64 {
 Mem::Mem() : flash(saveData) {
   rom.cart.resize(CART_SIZE);
   std::ranges::fill(rom.cart, 0);
+  isviewer_sink = std::ofstream("isviewer.log", std::ios::app);
 }
 
 void Mem::Reset() {

src/backend/core/Mem.hpp

@@ -140,6 +140,7 @@ private:
   void WriteJIT(u32, u64);
 
   std::array<u8, ISVIEWER_SIZE> isviewer{};
+  std::ofstream isviewer_sink{};
   int mmioSize{}, flashSize{};
   JIT *jit = nullptr;
   std::string sramPath{};

src/backend/core/mmio/PI.cpp

@@ -321,7 +321,8 @@ void PI::BusWrite<u32, false>(u32 addr, u32 val) {
         if (val < CART_ISVIEWER_SIZE) {
           std::string message(val + 1, 0);
           std::copy_n(mem.isviewer.begin(), val, message.begin());
-          always("{}", message);
+          mem.isviewer_sink << message;
+          mem.isviewer_sink.flush();
         } else {
           panic("ISViewer buffer size is emulated at {} bytes, but received a flush command for {} bytes!",
                       CART_ISVIEWER_SIZE, val);