feat(kiro): add AWS Builder ID authentication support

- Add --kiro-aws-login flag for AWS Builder ID device code flow
- Add DoKiroAWSLogin function for AWS SSO OIDC authentication
- Complete Kiro integration with AWS, Google OAuth, and social auth
- Add kiro executor, translator, and SDK components
- Update browser support for Kiro authentication flows

internal/auth/kiro/token.go

@@ -0,0 +1,72 @@
+package kiro
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+// KiroTokenStorage holds the persistent token data for Kiro authentication.
+type KiroTokenStorage struct {
+	// AccessToken is the OAuth2 access token for API access
+	AccessToken string `json:"access_token"`
+	// RefreshToken is used to obtain new access tokens
+	RefreshToken string `json:"refresh_token"`
+	// ProfileArn is the AWS CodeWhisperer profile ARN
+	ProfileArn string `json:"profile_arn"`
+	// ExpiresAt is the timestamp when the token expires
+	ExpiresAt string `json:"expires_at"`
+	// AuthMethod indicates the authentication method used
+	AuthMethod string `json:"auth_method"`
+	// Provider indicates the OAuth provider
+	Provider string `json:"provider"`
+	// LastRefresh is the timestamp of the last token refresh
+	LastRefresh string `json:"last_refresh"`
+}
+
+// SaveTokenToFile persists the token storage to the specified file path.
+func (s *KiroTokenStorage) SaveTokenToFile(authFilePath string) error {
+	dir := filepath.Dir(authFilePath)
+	if err := os.MkdirAll(dir, 0700); err != nil {
+		return fmt.Errorf("failed to create directory: %w", err)
+	}
+
+	data, err := json.MarshalIndent(s, "", "  ")
+	if err != nil {
+		return fmt.Errorf("failed to marshal token storage: %w", err)
+	}
+
+	if err := os.WriteFile(authFilePath, data, 0600); err != nil {
+		return fmt.Errorf("failed to write token file: %w", err)
+	}
+
+	return nil
+}
+
+// LoadFromFile loads token storage from the specified file path.
+func LoadFromFile(authFilePath string) (*KiroTokenStorage, error) {
+	data, err := os.ReadFile(authFilePath)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read token file: %w", err)
+	}
+
+	var storage KiroTokenStorage
+	if err := json.Unmarshal(data, &storage); err != nil {
+		return nil, fmt.Errorf("failed to parse token file: %w", err)
+	}
+
+	return &storage, nil
+}
+
+// ToTokenData converts storage to KiroTokenData for API use.
+func (s *KiroTokenStorage) ToTokenData() *KiroTokenData {
+	return &KiroTokenData{
+		AccessToken:  s.AccessToken,
+		RefreshToken: s.RefreshToken,
+		ProfileArn:   s.ProfileArn,
+		ExpiresAt:    s.ExpiresAt,
+		AuthMethod:   s.AuthMethod,
+		Provider:     s.Provider,
+	}
+}