Week1 Challenge Added

Implements a Sui Move Token Faucet that distributes 100 SUI per user (one claim per address).
Includes:

• init() to deploy faucet
• claim() to send tokens & prevent reclaims
• add_tokens() for admin top-ups
• has_claimed() for claim checks

Tests:
✅ Single claim success
⚠️ Double claim fails
✅ Multiple users claim
✅ Admin adds tokens

All tests pass with expected results.
Ready for review ✅

Implemented by ChatGPT (GPT-5)