feat: add stella-callgraph-node for JavaScript/TypeScript call graph extraction

- Implemented a new tool `stella-callgraph-node` that extracts call graphs from JavaScript/TypeScript projects using Babel AST.
- Added command-line interface with options for JSON output and help.
- Included functionality to analyze project structure, detect functions, and build call graphs.
- Created a package.json file for dependency management.

feat: introduce stella-callgraph-python for Python call graph extraction

- Developed `stella-callgraph-python` to extract call graphs from Python projects using AST analysis.
- Implemented command-line interface with options for JSON output and verbose logging.
- Added framework detection to identify popular web frameworks and their entry points.
- Created an AST analyzer to traverse Python code and extract function definitions and calls.
- Included requirements.txt for project dependencies.

chore: add framework detection for Python projects

- Implemented framework detection logic to identify frameworks like Flask, FastAPI, Django, and others based on project files and import patterns.
- Enhanced the AST analyzer to recognize entry points based on decorators and function definitions.

bench/reachability-benchmark/cases/go/grpc-sql/main.go

@@ -0,0 +1,86 @@
+// grpc-sql benchmark case
+// Demonstrates SQL injection sink reachable via gRPC handler
+package main
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"log"
+	"net"
+
+	_ "github.com/mattn/go-sqlite3"
+	"google.golang.org/grpc"
+)
+
+// User represents a user record
+type User struct {
+	ID    string
+	Name  string
+	Email string
+}
+
+// userServer implements the gRPC UserService
+type userServer struct {
+	db *sql.DB
+}
+
+// GetUser - VULNERABLE: SQL injection sink
+// User ID is concatenated directly into SQL query
+func (s *userServer) GetUser(ctx context.Context, userID string) (*User, error) {
+	// SINK: database/sql.Query with string concatenation
+	query := fmt.Sprintf("SELECT id, name, email FROM users WHERE id = '%s'", userID)
+	row := s.db.QueryRow(query)
+
+	var user User
+	if err := row.Scan(&user.ID, &user.Name, &user.Email); err != nil {
+		return nil, fmt.Errorf("user not found: %w", err)
+	}
+
+	return &user, nil
+}
+
+// GetUserSafe - SAFE: uses parameterized query
+func (s *userServer) GetUserSafe(ctx context.Context, userID string) (*User, error) {
+	query := "SELECT id, name, email FROM users WHERE id = ?"
+	row := s.db.QueryRow(query, userID)
+
+	var user User
+	if err := row.Scan(&user.ID, &user.Name, &user.Email); err != nil {
+		return nil, fmt.Errorf("user not found: %w", err)
+	}
+
+	return &user, nil
+}
+
+func main() {
+	db, err := sql.Open("sqlite3", ":memory:")
+	if err != nil {
+		log.Fatalf("failed to open database: %v", err)
+	}
+	defer db.Close()
+
+	// Initialize schema
+	_, err = db.Exec(`
+		CREATE TABLE users (
+			id TEXT PRIMARY KEY,
+			name TEXT,
+			email TEXT
+		)
+	`)
+	if err != nil {
+		log.Fatalf("failed to create table: %v", err)
+	}
+
+	lis, err := net.Listen("tcp", ":50051")
+	if err != nil {
+		log.Fatalf("failed to listen: %v", err)
+	}
+
+	s := grpc.NewServer()
+	// Register service here (simplified for benchmark)
+	log.Printf("gRPC server listening on %v", lis.Addr())
+	if err := s.Serve(lis); err != nil {
+		log.Fatalf("failed to serve: %v", err)
+	}
+}