Multi BLS added to new bls package

[tarakby]

Multi BLS added to new bls package

Summary

This PR continues the crypto package refactoring by integrating multi-signature BLS functionality into the new bls package structure. The changes include:

• Multi-signature BLS integration: Moved multi-signature BLS operations into the new bls package
• Common package removal: Eliminated the common package and restructured dependencies
• Import cycle resolution: Fixed import issues that arose during the refactoring
• C code formatting: Applied formatting fixes to maintain code standards

The PR builds on the foundational work from PR #33, specifically focusing on multi-signature capabilities within the modular package structure. All CI checks are passing, but the complexity of multi-signature cryptographic operations requires thorough manual verification.

Review & Testing Checklist for Human

• End-to-end multi-signature BLS testing - Verify multi-signature creation, aggregation, and verification work correctly with various key counts and thresholds
• Import cycle detection - Ensure no circular dependencies exist after common package removal and import restructuring
• Backward compatibility verification - Test that existing multi-signature BLS operations continue to work identically for downstream consumers
• Edge case testing - Test multi-signature scenarios with edge cases (single signer, maximum signers, invalid signatures, etc.)
• Common package removal impact - Verify that removing the common package didn't break existing functionality or introduce missing dependencies

Recommended Test Plan:

1. Run multi-signature BLS tests with various signer counts (1, 2, 10, 100+ signers)
2. Test signature aggregation and verification with real cryptographic inputs
3. Verify import statements compile correctly across all affected packages
4. Test integration with any downstream projects using multi-signature BLS
5. Compare multi-signature outputs before/after refactoring to ensure no logic changes

---

Diagram

%%{ init : { "theme" : "default" }}%%
graph TB
    subgraph "BLS Package Structure"
        BLSPkg["sign/bls/<br/>bls.go"]:::major-edit
        MultiBLS["sign/bls/<br/>multi_bls.go"]:::major-edit
        BLSTests["sign/bls/<br/>bls_test.go"]:::minor-edit
    end
    
    subgraph "Dependencies"
        BLS12381["bls12381/<br/>curve operations"]:::context
        SignPkg["sign/<br/>interfaces"]:::context
        CommonPkg["common/<br/>(removed)"]:::major-edit
    end
    
    subgraph "Import Fixes"
        ImportFixes["Various files<br/>import statements"]:::minor-edit
    end
    
    BLS12381 --> BLSPkg
    BLS12381 --> MultiBLS
    BLSPkg --> SignPkg
    MultiBLS --> SignPkg
    CommonPkg -.->|removed| BLSPkg
    CommonPkg -.->|removed| MultiBLS
    ImportFixes --> BLSPkg
    ImportFixes --> MultiBLS
    
    subgraph Legend
        L1["Major Edit"]:::major-edit
        L2["Minor Edit"]:::minor-edit
        L3["Context/No Edit"]:::context
    end
    
    classDef major-edit fill:#90EE90
    classDef minor-edit fill:#87CEEB
    classDef context fill:#FFFFFF

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Notes

• Link to Devin run: https://app.devin.ai/sessions/5cc7e1e8f7f0401999ebefe0c7610ca5
• Requested by: @tarakby
• Risk Level: 🔴 High - Multi-signature cryptographic operations are complex and security-critical; common package removal could have widespread impact
• Dependencies: This PR builds on the foundational refactoring from PR bls - ecdsa - bls12381 packages #33
• Critical: Multi-signature BLS operations must be thoroughly tested as they are used in consensus and security-critical applications