Add faucet-seed deterministic reset primitive so integration suites can rewind state

[thlpkee20-wq]

Description

Integration test suites need a faucet_reset(seed) primitive that deterministically restores the faucet to an initial state, so tests can be re-run without stale state.

Requirements and context

• Must be secure, tested, and documented
• Should be efficient and easy to review
• Relevant code: src/test_faucet_seed.rs, TESTNET_MODE.md
• Reset must only be callable when testnet_mode is enabled

Suggested execution

• Fork the repo and create a branch
• git checkout -b feat/faucet-reset
• Implement changes
  • Add faucet_reset(seed) gated on testnet_mode
  • Clear per-address cooldowns and metrics
  • Emit faucet_reset event with seed
• Validate security and correctness assumptions

Test and commit

• Run tests
  • cargo test --all
• Cover edge cases
  • Reset called on mainnet must revert
• Include test output and security notes

Example commit message

feat: add deterministic faucet reset primitive

Guidelines

• Minimum 95 percent test coverage
• Clear documentation
• Timeframe: 96 hours

[addnad]

hi maintainer, ive read through your description and i have worked on several issues like this, happy to take this if assign to me

[Purity-Euphemia]

Good Day Maintainer, I have experience and would review the issue, implement a clean solution, test it, and submit a pull request.