fix: enforce signature ordering


**Description**
Sort signatures.

**Problem Statement**
Ordering bugs.

**Technical Requirements**
- [ ] Sort addrs/sigs.

**Implementation Guide**
- **Suggested Approach:** Strict sort check.
- **Affected Areas:** src/

**Acceptance Criteria**
- [ ] Valid ordering only.

**Security & Audit Considerations**
- [ ] None.

**Definition of Done**
- [ ] Ordering confirmed.