Educational faucet for simulated funds (`faucet.rs`)

[DevMuhdishaq]

Description
As an educational simulator, new users need a way to obtain simulated tokens to start trading. Add a rate-limited faucet.

Direction

• Create counter/src/faucet.rs with claim_faucet(env, user, asset) minting a fixed simulated amount.
• Enforce a cooldown per user/asset using the existing rate_limit module.
• Admin-configurable per-asset drip amount and cooldown.
• Emit a FaucetClaimed event.

Acceptance criteria

• First claim mints the configured amount and updates balance.
• Second claim within cooldown rejects with a rate-limit error.
• Claim after cooldown succeeds.
• Admin can set drip amount and cooldown; non-admin cannot.
• Tests cover cooldown boundaries via ledger timestamp manipulation.

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[Okorie2000-code]

Hi maintainer, would love to work on this issue, i have already reviewed the description and will submit a clean PR. kindly assign.

[obswrld]

I would like to work on this issue.

[grantfox-oss]

🦊 GrantFox — @obswrld has been assigned to this issue as part of the Official Campaign | FWC26 campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #213)
2. Your PR will be reviewed by the StelTade maintainers

Good luck! Track your progress on GrantFox.

[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox as part of the Official Campaign | FWC26 campaign!

@obswrld's PR #229 was approved and merged by @DevMuhdishaq.

🏆 @obswrld: You earned 35 FoxPoints for this contribution! Your current tier: Explorer (446 total points). Track your full progress on GrantFox.

👏 Great work, @obswrld! Keep contributing to StelTade.