Implement Soroban Rule Suppression Framework

[mijinummi]

🧠 Concept

Allow developers to suppress specific rule findings intentionally.

⚠️ Problem

Certain findings may be acceptable in specific contract designs.

📁 Implementation Scope

• src/suppressions/stellar/

✅ Requirements

• Support inline suppressions
• Support configuration-based suppressions
• Record suppression reasons

🎯 Acceptance Criteria

• Rule suppression framework implemented
• Suppressed findings excluded from reports