[Codebase Audit] Reduce panic-prone calls in `src/aml/ctr_tests.rs`

[kelly-musk]

Problem

src/aml/ctr_tests.rs contains 32 panic-prone calls (unwrap, expect, or panic!).

Evidence

• src/aml/ctr_tests.rs:21 — let amount1 = Decimal::from_str("1000000").unwrap();
• src/aml/ctr_tests.rs:22 — let amount2 = Decimal::from_str("2500000").unwrap();
• src/aml/ctr_tests.rs:23 — let amount3 = Decimal::from_str("1500000").unwrap();
• src/aml/ctr_tests.rs:26 — assert_eq!(total, Decimal::from_str("5000000").unwrap());
• src/aml/ctr_tests.rs:32 — let usd_amount = Decimal::from_str("1000").unwrap();

Proposed fix

Replace non-essential unwrap/expect usages with typed error propagation and contextual logging. Keep explicit panics only where unrecoverable invariants are well-documented.

Acceptance criteria

• All avoidable panic-prone calls in this file are removed or justified with comments/tests.
• Error paths return typed errors and preserve observability context.
• Existing tests pass (or new tests cover changed paths).

[Tobiloba0]

@Tobiloba0 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi maintainer, as a software engineer, I can finish this issue in 15 minutes.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Tobiloba0 to this issue.