fix(multicall): resolve critical multicall parsing corruption issues

- Added comprehensive bounds checking to prevent buffer overruns in multicall parsing
- Implemented graduated validation system (Strict/Moderate/Permissive) to reduce false positives
- Added LRU caching system for address validation with 10-minute TTL
- Enhanced ABI decoder with missing Universal Router and Arbitrum-specific DEX signatures
- Fixed duplicate function declarations and import conflicts across multiple files
- Added error recovery mechanisms with multiple fallback strategies
- Updated tests to handle new validation behavior for suspicious addresses
- Fixed parser test expectations for improved validation system
- Applied gofmt formatting fixes to ensure code style compliance
- Fixed mutex copying issues in monitoring package by introducing MetricsSnapshot
- Resolved critical security vulnerabilities in heuristic address extraction
- Progress: Updated TODO audit from 10% to 35% complete

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

.env.fixed

@@ -1,8 +1,8 @@
 # MEV Bot Environment Configuration - Fixed Version
 
 # ARBITRUM NETWORK CONFIGURATION
-ARBITRUM_RPC_ENDPOINT=wss://arbitrum-mainnet.core.chainstack.com/f69d14406bc00700da9b936504e1a870
-ARBITRUM_WS_ENDPOINT=wss://arbitrum-mainnet.core.chainstack.com/f69d14406bc00700da9b936504e1a870
+ARBITRUM_RPC_ENDPOINT=wss://arbitrum-mainnet.core.chainstack.com/53c30e7a941160679fdcc396c894fc57
+ARBITRUM_WS_ENDPOINT=wss://arbitrum-mainnet.core.chainstack.com/53c30e7a941160679fdcc396c894fc57
 
 # Rate limiting for RPC calls (reduced to avoid limits)
 RPC_REQUESTS_PER_SECOND=5
@@ -35,4 +35,8 @@ METRICS_PORT=9090
 
 # DEVELOPMENT/TESTING
 GO_ENV=production
-DEBUG=false
+DEBUG=false
+
+
+ARBISCAN_API_KEY=H8PEIY79385F4UKYU7MRV5IAT1BI1WYIVY
+