Implement Soroban TTL Analyzer

[mijinummi]

🧠 Concept

Analyze TTL configuration and expiration patterns in Soroban contracts.

⚠️ Problem

Poor TTL management can cause unexpected state expiration or unnecessary storage maintenance.

📁 Implementation Scope

• packages/analyzers/soroban/ttl/
• packages/rules/soroban/ttl/

✅ Requirements

• Detect TTL-related operations
• Identify missing TTL extensions
• Detect unusually short TTL values
• Generate actionable findings

🎯 Acceptance Criteria

• TTL analyzer implemented
• TTL patterns detected
• Risky configurations reported
• Tests added

[Nuruddeen61]

Hey @mijinummi, I'd like to work on this.

Experience: I've built Soroban contracts and dealt with TTL expiration issues on testnet. Familiar with AST analysis.

Approach:

1. Build analyzer in packages/analyzers/soroban/ttl/ to detect storage.set(), extend_ttl() calls and TTL values
2. Create rules in packages/rules/soroban/ttl/ to flag missing extensions and TTL < 17280 ledgers (~30 days)
3. Generate findings with file:line and recommended fix
4. Add tests with sample contracts showing good/bad TTL patterns

I can deliver initial implementation in 1-2 days.