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>

test/testutils/testutils.go

@@ -7,14 +7,23 @@ import (
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/holiman/uint256"
+
 	"github.com/fraktal/mev-beta/internal/config"
 	"github.com/fraktal/mev-beta/internal/logger"
 	"github.com/fraktal/mev-beta/pkg/events"
 	"github.com/fraktal/mev-beta/pkg/market"
 	"github.com/fraktal/mev-beta/pkg/scanner"
-	"github.com/holiman/uint256"
 )
 
+// safeConvertInt64ToUint64 safely converts an int64 to uint64, ensuring no negative values
+func safeConvertInt64ToUint64(v int64) uint64 {
+	if v < 0 {
+		return 0
+	}
+	return uint64(v)
+}
+
 // CreateTestConfig creates a test configuration
 func CreateTestConfig() *config.Config {
 	return &config.Config{
@@ -77,7 +86,7 @@ func CreateTestEvent() *events.Event {
 		SqrtPriceX96:    uint256.NewInt(2505414483750470000),
 		Liquidity:       uint256.NewInt(1000000000000000000),
 		Tick:            200000,
-		Timestamp:       uint64(time.Now().Unix()),
+		Timestamp:       safeConvertInt64ToUint64(time.Now().Unix()),
 		TransactionHash: common.HexToHash("0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef"),
 		BlockNumber:     12345,
 	}
@@ -102,7 +111,7 @@ func CreateTestMarketManager() *market.MarketManager {
 }
 
 // CreateTestScanner creates a test market scanner
-func CreateTestScanner() *scanner.MarketScanner {
+func CreateTestScanner() *scanner.Scanner {
 	cfg := &config.BotConfig{
 		MaxWorkers:         5,
 		ChannelBufferSize:  10,
@@ -110,7 +119,7 @@ func CreateTestScanner() *scanner.MarketScanner {
 		MinProfitThreshold: 10.0,
 	}
 	logger := CreateTestLogger()
-	return scanner.NewMarketScanner(cfg, logger)
+	return scanner.NewScanner(cfg, logger, nil, nil)
 }
 
 // CreateTestPipeline creates a test pipeline