keep hard mode hints when resuming a game

hard_mode_check uses the previous row's greens and yellows, but these
weren't written to the progress file, so after resuming a game the next
guess could drop known green and yellow letters. Save them alongside
the rest of the game state.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

wordle

@@ -409,6 +409,15 @@ function save_game() {
     echo "KEYS[$key]='${KEYS[$key]}'" >> "${PROGRESS_FILE}"
   done
 
+  # Previous row's hints, needed by hard_mode_check after a resume
+  for key in "${!greens[@]}"; do
+    echo "greens[$key]='${greens[$key]}'" >> "${PROGRESS_FILE}"
+  done
+
+  for key in "${!yellows[@]}"; do
+    echo "yellows[$key]='${yellows[$key]}'" >> "${PROGRESS_FILE}"
+  done
+
   {
     echo "ROW=${row}"
     echo "POOL=${POOL}"