refactor: move JWTConfig to config package and update database initialization methods

backend/internal/api/middleware/jwt_auth.go

@@ -73,7 +73,7 @@ func fileExists(path string) bool {
 }
 
 // generateRSAKeys generates RSA keys and saves them to disk
-func generateRSAKeys(cfg models.JWTConfig) error {
+func generateRSAKeys(cfg config.JWTConfig) error {
 	// Create key directory if it doesn't exist
 	if err := os.MkdirAll(cfg.KeyDir, 0700); err != nil {
 		return fmt.Errorf("failed to create key directory: %w", err)