feat: add configurable test mode and rate limiting

- Add TestMode, RateLimitEnabled, RequestsPerMinute to Config
- Add getEnvBool() and getEnvInt() helper functions
- Update rate limiter to support enabled/disabled state
- Pass test environment variables through docker-compose
- Configure rate limiter dynamically in main.go

This allows disabling rate limiting for integration testing while
maintaining security in production environments.

internal/config/config.go

@@ -3,29 +3,36 @@ package config
 import (
 	"fmt"
 	"os"
+	"strconv"
 )
 
 type Config struct {
-	ServerPort       string
-	JWTSecret        string
-	UploadPath       string
-	DatabaseHost     string
-	DatabasePort     string
-	DatabaseUser     string
-	DatabasePassword string
-	DatabaseName     string
+	ServerPort        string
+	JWTSecret         string
+	UploadPath        string
+	DatabaseHost      string
+	DatabasePort      string
+	DatabaseUser      string
+	DatabasePassword  string
+	DatabaseName      string
+	TestMode          bool
+	RateLimitEnabled  bool
+	RequestsPerMinute int
 }
 
 func LoadConfig() *Config {
 	return &Config{
-		ServerPort:       getEnv("SERVER_PORT", "8080"),
-		DatabaseHost:     getEnv("DATABASE_HOST", "localhost"),
-		DatabasePort:     getEnv("DATABASE_PORT", "5432"),
-		DatabaseUser:     getEnv("DATABASE_USER", "postgres"),
-		DatabasePassword: getEnv("DATABASE_PASSWORD", "password"),
-		DatabaseName:     getEnv("DATABASE_NAME", "bookmann"),
-		JWTSecret:        getEnv("JWT_SECRET", "your-secret-key"),
-		UploadPath:       getEnv("UPLOAD_PATH", "./uploads"),
+		ServerPort:        getEnv("SERVER_PORT", "8080"),
+		DatabaseHost:      getEnv("DATABASE_HOST", "localhost"),
+		DatabasePort:      getEnv("DATABASE_PORT", "5432"),
+		DatabaseUser:      getEnv("DATABASE_USER", "postgres"),
+		DatabasePassword:  getEnv("DATABASE_PASSWORD", "password"),
+		DatabaseName:      getEnv("DATABASE_NAME", "bookmann"),
+		JWTSecret:         getEnv("JWT_SECRET", "your-secret-key"),
+		UploadPath:        getEnv("UPLOAD_PATH", "./uploads"),
+		TestMode:          getEnvBool("TEST_MODE", false),
+		RateLimitEnabled:  getEnvBool("RATE_LIMIT_ENABLED", true),
+		RequestsPerMinute: getEnvInt("REQUESTS_PER_MINUTE", 10),
 	}
 }
 
@@ -40,3 +47,23 @@ func getEnv(key, defaultValue string) string {
 	}
 	return defaultValue
 }
+
+func getEnvBool(key string, defaultValue bool) bool {
+	if value := os.Getenv(key); value != "" {
+		boolVal, err := strconv.ParseBool(value)
+		if err == nil {
+			return boolVal
+		}
+	}
+	return defaultValue
+}
+
+func getEnvInt(key string, defaultValue int) int {
+	if value := os.Getenv(key); value != "" {
+		intVal, err := strconv.Atoi(value)
+		if err == nil {
+			return intVal
+		}
+	}
+	return defaultValue
+}