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>

internal/ratelimit/adaptive.go

@@ -7,9 +7,10 @@ import (
 	"sync/atomic"
 	"time"
 
+	"golang.org/x/time/rate"
+
 	"github.com/fraktal/mev-beta/internal/config"
 	"github.com/fraktal/mev-beta/internal/logger"
-	"golang.org/x/time/rate"
 )
 
 // AdaptiveRateLimiter implements adaptive rate limiting that adjusts to endpoint capacity

internal/ratelimit/manager.go

@@ -5,8 +5,9 @@ import (
 	"fmt"
 	"sync"
 
-	"github.com/fraktal/mev-beta/internal/config"
 	"golang.org/x/time/rate"
+
+	"github.com/fraktal/mev-beta/internal/config"
 )
 
 // LimiterManager manages rate limiters for multiple endpoints

internal/ratelimit/manager_test.go

@@ -5,9 +5,10 @@ import (
 	"testing"
 	"time"
 
-	"github.com/fraktal/mev-beta/internal/config"
 	"github.com/stretchr/testify/assert"
 	"golang.org/x/time/rate"
+
+	"github.com/fraktal/mev-beta/internal/config"
 )
 
 func TestNewLimiterManager(t *testing.T) {
@@ -18,15 +19,24 @@ func TestNewLimiterManager(t *testing.T) {
 			RequestsPerSecond: 10,
 			Burst:             20,
 		},
-		FallbackEndpoints: []config.EndpointConfig{
+		ReadingEndpoints: []config.EndpointConfig{
 			{
-				URL: "https://fallback.arbitrum.io/rpc",
+				URL: "https://read.arbitrum.io/rpc",
 				RateLimit: config.RateLimitConfig{
 					RequestsPerSecond: 5,
 					Burst:             10,
 				},
 			},
 		},
+		ExecutionEndpoints: []config.EndpointConfig{
+			{
+				URL: "https://exec.arbitrum.io/rpc",
+				RateLimit: config.RateLimitConfig{
+					RequestsPerSecond: 3,
+					Burst:             6,
+				},
+			},
+		},
 	}
 
 	// Create limiter manager
@@ -35,7 +45,7 @@ func TestNewLimiterManager(t *testing.T) {
 	// Verify limiter manager was created correctly
 	assert.NotNil(t, lm)
 	assert.NotNil(t, lm.limiters)
-	assert.Len(t, lm.limiters, 2) // Primary + 1 fallback
+	assert.Len(t, lm.limiters, 3) // Primary + 1 fallback
 
 	// Check primary endpoint limiter
 	primaryLimiter, exists := lm.limiters[cfg.RPCEndpoint]
@@ -45,10 +55,10 @@ func TestNewLimiterManager(t *testing.T) {
 	assert.NotNil(t, primaryLimiter.Limiter)
 
 	// Check fallback endpoint limiter
-	fallbackLimiter, exists := lm.limiters[cfg.FallbackEndpoints[0].URL]
+	fallbackLimiter, exists := lm.limiters[cfg.ReadingEndpoints[0].URL]
 	assert.True(t, exists)
-	assert.Equal(t, cfg.FallbackEndpoints[0].URL, fallbackLimiter.URL)
-	assert.Equal(t, cfg.FallbackEndpoints[0].RateLimit, fallbackLimiter.Config)
+	assert.Equal(t, cfg.ReadingEndpoints[0].URL, fallbackLimiter.URL)
+	assert.Equal(t, cfg.ReadingEndpoints[0].RateLimit, fallbackLimiter.Config)
 	assert.NotNil(t, fallbackLimiter.Limiter)
 }
 
@@ -172,7 +182,7 @@ func TestGetEndpoints(t *testing.T) {
 			RequestsPerSecond: 10,
 			Burst:             20,
 		},
-		FallbackEndpoints: []config.EndpointConfig{
+		ReadingEndpoints: []config.EndpointConfig{
 			{
 				URL: "https://fallback1.arbitrum.io/rpc",
 				RateLimit: config.RateLimitConfig{
@@ -199,8 +209,8 @@ func TestGetEndpoints(t *testing.T) {
 	// Verify results
 	assert.Len(t, endpoints, 3) // Primary + 2 fallbacks
 	assert.Contains(t, endpoints, cfg.RPCEndpoint)
-	assert.Contains(t, endpoints, cfg.FallbackEndpoints[0].URL)
-	assert.Contains(t, endpoints, cfg.FallbackEndpoints[1].URL)
+	assert.Contains(t, endpoints, cfg.ReadingEndpoints[0].URL)
+	assert.Contains(t, endpoints, cfg.ReadingEndpoints[1].URL)
 }
 
 func TestRateLimiting(t *testing.T) {