Fix #41: Handle large numbers safely in millify using BigInt

[baraich]

Problem:

The millify library throws a warning when the input value exceeds JavaScript’s safe integer range (-(2^53 - 1) to (2^53 - 1)), causing incorrect behavior when trying to format large numbers such as 210000000000000000.

Changes:

• Added a new safeMillify function that:
  • Converts large numbers to BigInt.
  • Scales down numbers outside the safe range.
  • Passes the scaled number to millify for formatting.
  • Reapplies the original scale after millification.

Note

I have replaced the default millify function with safeMillify, though it is exported as the same name. Should we consider exporting safeMillify seperately?