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>

pkg/trading/slippage_protection.go

@@ -11,10 +11,19 @@ import (
 	"github.com/ethereum/go-ethereum"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/ethclient"
+
 	"github.com/fraktal/mev-beta/internal/logger"
 	"github.com/fraktal/mev-beta/pkg/validation"
 )
 
+// safeConvertInt64ToUint64 safely converts an int64 to uint64, ensuring no negative values
+func safeConvertInt64ToUint64(v int64) uint64 {
+	if v < 0 {
+		return 0
+	}
+	return uint64(v)
+}
+
 // SlippageProtection provides comprehensive slippage protection for trades
 type SlippageProtection struct {
 	validator          *validation.InputValidator
@@ -345,7 +354,7 @@ func (sp *SlippageProtection) CreateSafeTradeParameters(
 	minAmountOutInt, _ := minAmountOut.Int(nil)
 
 	// Set deadline to 5 minutes from now
-	deadline := uint64(time.Now().Add(5 * time.Minute).Unix())
+	deadline := safeConvertInt64ToUint64(time.Now().Add(5 * time.Minute).Unix())
 
 	return &TradeParameters{
 		TokenIn:          tokenIn,