[chigozirim007]

Summary

Implements the "Automated Rent-Drip" inter-contract hook: a Susu circle winner can authorize claim_pot to send their pot payout directly to a LeaseFlow LeaseInstance contract instead of their own wallet, so a tenant group is never late on rent during their winning month.

closes #105

Changes

• LeaseInstanceClient (#[contractclient]): minimal pay_rent(tenant, token, amount) interface a LeaseFlow LeaseInstance contract must expose, mirroring the existing SusuNftClient/LendingPoolClient pattern.
• DataKey::RentDripAuthorization(Address, u64): per-member, per-circle opt-in storage.
• authorize_rent_drip(user, circle_id, lease_instance): requires user.require_auth() and that the caller is an existing member of that circle.
• revoke_rent_drip(user, circle_id): clears the authorization.
• claim_pot: if the winner has an active authorization for the circle, the pot is transferred to the LeaseInstance contract and pay_rent is invoked on it, instead of transferring to the winner's own address. Unauthorized winners keep the existing direct-payout behavior unchanged.

Test plan

New tests/rent_drip_test.rs (5 tests, all passing):

• claim_pot_pays_the_winner_directly_without_authorization: baseline, unauthorized behavior unchanged.
• authorize_rent_drip_routes_the_payout_to_the_lease_instance: pot lands on the LeaseInstance contract, not the winner's wallet, and the mock LeaseInstance records the pay_rent call with the right tenant/amount.
• revoke_rent_drip_restores_direct_payout_to_the_winner: revoking returns to direct payout.
• authorize_rent_drip_rejects_a_non_member / authorize_rent_drip_rejects_an_unknown_circle: auth guard failure modes.

Ran with cargo test/cargo clippy --all-targets/cargo fmt --check on Rust 1.89 (this machine's default rustup toolchain, 1.99.0, fails to build the pre-existing ethnum dependency entirely with an unrelated E0512 transmute error; confirmed via git stash that this also fails on a clean checkout of main, so it is a local toolchain/environment issue, not something introduced here). All existing tests still pass; cargo clippy --test hyper_inflation_test also pre-existingly fails (absurd_extreme_comparisons on amount <= i128::MAX), confirmed via the same git stash check, unrelated to this change.