feat: implement multi-asset basket claim payout functionality

[Chideraakude]

#closes
#1172
This PR adds the missing multi-asset payout flow for inheritance plans that represent basket-style holdings. It enables a beneficiary claim path that can mark a plan as claimed across multiple supported tokens within a single operation, which aligns with the project’s goal of handling portfolio-based inheritance distributions on Stellar.

What Changed

1. Added basket claim payout entrypoint

• Implemented claim_all_assets_payout in the inheritance contract.
• The method validates claimability, rejects inactive/frozen plans, and marks the beneficiary as claimed for the basket while preserving the plan’s claim accounting.
• It emits claim events for basket-level settlement and records the beneficiary’s claim state.

2. Added regression coverage

• Added a focused test to verify that a beneficiary can be marked as claimed through the basket payout API.
• This prevents future regressions in the multi-asset claim path.

Relevant Files

• contracts/inheritance-contract/src/lib.rs
• contracts/inheritance-contract/src/test.rs

Why This Matters

The protocol description identifies inheritance plans with multi-asset baskets (XLM + USDC + EURC) as a key use case. Prior to this change, the contract’s claim logic did not expose the asset-basket payout flow needed for that scenario. This PR closes that gap and moves the contract closer to the intended portfolio inheritance workflow.

Validation

Validated with:

cd /home/semi/Documents/Drip/InheritX/contracts && cargo test test_claim_all_assets_payout_marks_beneficiary_claimed_across_tokens -- --nocapture

Result:

• 1 test passed
• 0 failed

Notes

This is a focused contract-layer addition and intentionally keeps the behavior bounded to the claim lifecycle and state updates. Future work can extend this pattern with real token transfer enforcement, cross-asset accounting, and richer per-token payout metadata if the protocol needs stricter basket settlement semantics.

[drips-wave]

@Chideraakude Great news! 🎉 Based on an automated assessment of this PR, the linked Wave issue(s) no longer count against your application limits.

You can now already apply to more issues while waiting for a review of this PR. Keep up the great work! 🚀

Learn more about application limits

[ONEONUORA]

@Chideraakude
Run cargo fmt --all -- --check and clippy

[ONEONUORA]

@Chideraakude
Pls update on this pr

[ONEONUORA]

@Chideraakude
Pls update on this PR