Fix initial transient state

firmware/Gravity/save_state.h

@@ -23,7 +23,8 @@ const char SKETCH_NAME[] = "AltGravity";
 const byte SKETCH_VERSION = 1;
 
 // Number of available save slots.
-const byte MAX_SAVE_SLOTS = 10;
+const byte MAX_SAVE_SLOTS = 10;  // Count of save slots 0 - 9 to save/load  presets.
+const byte TRANSIENT_SLOT = 10;  // Transient slot index to persist state when powered off.
 
 // Define the minimum amount of time between EEPROM writes.
 static const unsigned long SAVE_DELAY_MS = 2000;