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>

tools/math-audit/internal/loader/loader.go

@@ -0,0 +1,115 @@
+package loader
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/fraktal/mev-beta/tools/math-audit/internal/models"
+)
+
+const defaultVectorDir = "tools/math-audit/vectors"
+
+// LoadVectors loads vectors based on the selector. The selector can be:
+//   - "default" (load all embedded vectors)
+//   - a comma-separated list of files or directories.
+func LoadVectors(selector string) ([]models.Vector, error) {
+	if selector == "" || selector == "default" {
+		return loadFromDir(defaultVectorDir)
+	}
+
+	var all []models.Vector
+	parts := strings.Split(selector, ",")
+	for _, part := range parts {
+		part = strings.TrimSpace(part)
+		if part == "" {
+			continue
+		}
+
+		info, err := os.Stat(part)
+		if err != nil {
+			return nil, fmt.Errorf("stat %s: %w", part, err)
+		}
+
+		if info.IsDir() {
+			vecs, err := loadFromDir(part)
+			if err != nil {
+				return nil, err
+			}
+			all = append(all, vecs...)
+			continue
+		}
+
+		vec, err := loadFromFile(part)
+		if err != nil {
+			return nil, err
+		}
+		all = append(all, vec)
+	}
+
+	return all, nil
+}
+
+func loadFromDir(dir string) ([]models.Vector, error) {
+	entries, err := os.ReadDir(dir)
+	if err != nil {
+		return nil, fmt.Errorf("read dir %s: %w", dir, err)
+	}
+
+	var vectors []models.Vector
+	for _, entry := range entries {
+		if entry.IsDir() {
+			continue
+		}
+		if !strings.HasSuffix(entry.Name(), ".json") {
+			continue
+		}
+
+		path := filepath.Join(dir, entry.Name())
+		vec, err := loadFromFile(path)
+		if err != nil {
+			return nil, err
+		}
+		vectors = append(vectors, vec)
+	}
+
+	return vectors, nil
+}
+
+func loadFromFile(path string) (models.Vector, error) {
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return models.Vector{}, fmt.Errorf("read vector %s: %w", path, err)
+	}
+
+	var vec models.Vector
+	if err := json.Unmarshal(data, &vec); err != nil {
+		return models.Vector{}, fmt.Errorf("decode vector %s: %w", path, err)
+	}
+
+	if err := vec.Validate(); err != nil {
+		return models.Vector{}, fmt.Errorf("validate vector %s: %w", path, err)
+	}
+
+	return vec, nil
+}
+
+// WalkVectors walks every vector JSON file in a directory hierarchy.
+func WalkVectors(root string, fn func(path string, vec models.Vector) error) error {
+	return filepath.WalkDir(root, func(path string, d fs.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+		if d.IsDir() || !strings.HasSuffix(d.Name(), ".json") {
+			return nil
+		}
+		vec, err := loadFromFile(path)
+		if err != nil {
+			return err
+		}
+		return fn(path, vec)
+	})
+}