Implement Soroban Event Topic Consistency Rule

[mijinummi]

🧠 Concept

Validate consistency of event topics across contract functions.

⚠️ Problem

Inconsistent event topics make indexing and downstream integrations harder.

📁 Implementation Scope

• packages/rules/soroban/events/
• packages/analyzers/soroban/events/

✅ Requirements

• Extract event topics
• Compare related events
• Detect inconsistent naming
• Report affected functions

🎯 Acceptance Criteria

• Topic consistency rule implemented
• Related events compared
• Inconsistencies reported
• Tests added