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/stress/benchmarks.go

@@ -1,3 +1,6 @@
+//go:build stress
+// +build stress
+
 package stress_test
 
 import (
@@ -11,6 +14,8 @@ import (
 	"time"
 
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/holiman/uint256"
+
 	"github.com/fraktal/mev-beta/internal/logger"
 	"github.com/fraktal/mev-beta/pkg/arbitrum"
 	"github.com/fraktal/mev-beta/pkg/events"
@@ -18,7 +23,6 @@ import (
 	"github.com/fraktal/mev-beta/pkg/profitcalc"
 	"github.com/fraktal/mev-beta/pkg/scanner/market"
 	"github.com/fraktal/mev-beta/pkg/trading"
-	"github.com/holiman/uint256"
 )
 
 // BenchmarkStressTestSuite runs benchmark tests for the stress test suite

test/stress/stress_test_runner.go

@@ -1,3 +1,6 @@
+//go:build stress
+// +build stress
+
 package stress_test
 
 import (
@@ -13,6 +16,8 @@ import (
 	"time"
 
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/holiman/uint256"
+
 	"github.com/fraktal/mev-beta/internal/logger"
 	"github.com/fraktal/mev-beta/pkg/arbitrum"
 	"github.com/fraktal/mev-beta/pkg/events"
@@ -21,7 +26,6 @@ import (
 	"github.com/fraktal/mev-beta/pkg/profitcalc"
 	"github.com/fraktal/mev-beta/pkg/scanner/market"
 	"github.com/fraktal/mev-beta/pkg/scanner/swap"
-	"github.com/holiman/uint256"
 )
 
 // StressTestRunner runs comprehensive stress tests for the MEV bot

test/stress/stress_test_suite.go

@@ -1,3 +1,6 @@
+//go:build stress
+// +build stress
+
 package stress_test
 
 import (
@@ -10,6 +13,8 @@ import (
 	"time"
 
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/holiman/uint256"
+
 	"github.com/fraktal/mev-beta/internal/logger"
 	"github.com/fraktal/mev-beta/pkg/arbitrum"
 	"github.com/fraktal/mev-beta/pkg/events"
@@ -18,7 +23,6 @@ import (
 	"github.com/fraktal/mev-beta/pkg/scanner/market"
 	"github.com/fraktal/mev-beta/pkg/scanner/swap"
 	"github.com/fraktal/mev-beta/pkg/trading"
-	"github.com/holiman/uint256"
 )
 
 // StressTestSuite manages stress testing of MEV bot components