Implement Soroban Authorization Tree Analyzer

[mijinummi]

🧠 Concept

Build a structured representation of Soroban authorization requirements.

⚠️ Problem

Complex authorization flows are difficult to audit from isolated source-level findings.

📁 Implementation Scope

• packages/analyzers/soroban/auth/tree/
• packages/rules/soroban/auth/

✅ Requirements

• Track authorization requirements
• Build authorization relationships
• Identify nested checks
• Expose authorization tree data

🎯 Acceptance Criteria

• Authorization tree implemented
• Nested checks represented
• Relationships tracked
• Tests added