1. Add Challenge Mode and corresponding achievements

Challenge Mode:
At the start of the game, you can freely choose your team members, allowing a combination of up to
four characters. You cannot enter the Rebirth phase, and being defeated simply means the game ends.
The acquisition rates of Rebirth Crystals, Gold, Imprints, and Void Orbs are increased.

2. Modified the appearance of some NPCs.

3. Fixed some text errors and bugs.