feat: batch claim inheritance payouts

[d3v-active]

Closes #1042

This PR implements the batch_claim_inheritance_plan entry point in contracts/inheritance-contract/src/lib.rs for multi-beneficiary payouts.

Changes Included

• Added batch_claim_inheritance_plan(env: Env, plan_id: u64, claimer: Address, beneficiary_indices: Vec<u32>, claim_codes: Vec<u32>)
• Refactored logic to iterate over the beneficiary_indices to process multiple claims atomically within a single transaction.
• Maintained exact behavior of all per-beneficiary and aggregate limits, vesting logic, and KYC protections as the original single claim_inheritance_plan function.
• Ensures atomicity: if any single beneficiary's verification fails, the entire transaction reverts.

[ONEONUORA]

@d3v-active

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

[d3v-active]

@d3v-active

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

ok boss. on it