Implement issues #292, #294, #293: Expensive String Ops, Nested Loops…

[fadee26]

Description

This PR implements three new rules for Solidity analysis:

1. sol-010 - Expensive String Operations

   • Detects costly string manipulation (concatenation, assignments)
   • Recommends using bytes types instead for gas efficiency

2. sol-011 - Nested Loop Gas Risk

   • Finds nested loops (depth >1) that can consume excessive gas
   • Warns about potential block gas limit violations

3. sol-012 - Missing Event Emissions

   • Flags state-changing functions that don't emit events
   • Improves auditability and transparency
     Additionally, fixes syntax errors in the existing sol-009 (Missing Timelock) rule implementation that were causing compilation issues.

Changes

• Updated libs/engine/analyzers/solidity-analyzer.ts
• Added new rule definitions to SolidityAnalyzer.rules
• Implemented detectExpensiveStringOperations()
• Implemented detectNestedLoops()
• Implemented detectMissingEventEmissions()
• Added rule checks in analyze() method
• Fixed sol-009 implementation (detectMissingTimelockForSensitiveOperations)

closes #292 
closes #294 
closes #293 

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@fadee26 Great news! 🎉 Based on an automated assessment of this PR, the linked Wave issue(s) no longer count against your application limits.

You can now already apply to more issues while waiting for a review of this PR. Keep up the great work! 🚀

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