Convert stored_calories on character template load

Before CleverRaven#46906, character templates were saved with stored_calories equal
to total kilocalories (55,000 being the "healthy" baseline).

Now, stored_calories is in units of small-c calories, being 55,000,000
for the healthy baseline. This led to a bug CleverRaven#46995 where new characters
created from older-version templates would spawn with too few calories,
by a factor of 1,000.

Detect this when templates are loaded, and multiply stored_calories if
its value appears to be way too small.

src/newcharacter.cpp

@@ -3633,6 +3633,12 @@ bool avatar::load_template( const std::string &template_name, points_left &point
 
         deserialize( jsin );
 
+        // If stored_calories the template is under a million (kcals < 1000), assume it predates the
+        // kilocalorie-to-literal-calorie conversion and is off by a factor of 1000.
+        if( get_stored_kcal() < 1000 ) {
+            set_stored_kcal( 1000 * get_stored_kcal() );
+        }
+
         if( MAP_SHARING::isSharing() ) {
             // just to make sure we have the right name
             name = MAP_SHARING::getUsername();