Fix emulator build script, UI rendering, and clean up repo

lib/serial_uploader.h

@@ -12,7 +12,8 @@ public:
 
     // Process incoming serial data (call this frequently in main loop)
     // Returns true if a game was launched
-    bool process();
+    // spi_busy: set to true if SPI bus is currently in use by another core (e.g. display refresh)
+    bool process(bool spi_busy = false);
 
     // Check if uploader wants to launch a game (after upload complete)
     bool wants_to_launch_game() const { return state == LAUNCHING_GAME; }