refactor(auth): replace TokenRecord with coreauth.Auth and migrate TokenStore to coreauth.Store

- Replaced `TokenRecord` with `coreauth.Auth` for centralized and consistent authentication data structures.
- Migrated `TokenStore` interface to `coreauth.Store` for alignment with core CLIProxy authentication.
- Updated related login methods, token persistence logic, and file storage handling to use the new `coreauth.Auth` model.

sdk/auth/interfaces.go

@@ -5,8 +5,8 @@ import (
 	"errors"
 	"time"
 
-	baseauth "github.com/router-for-me/CLIProxyAPI/v6/internal/auth"
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/config"
+	coreauth "github.com/router-for-me/CLIProxyAPI/v6/sdk/cliproxy/auth"
 )
 
 var ErrRefreshNotSupported = errors.New("cliproxy auth: refresh not supported")
@@ -20,22 +20,9 @@ type LoginOptions struct {
 	Prompt    func(prompt string) (string, error)
 }
 
-// TokenRecord represents credential material produced by an authenticator.
-type TokenRecord struct {
-	Provider string
-	FileName string
-	Storage  baseauth.TokenStorage
-	Metadata map[string]string
-}
-
-// TokenStore persists token records.
-type TokenStore interface {
-	Save(ctx context.Context, cfg *config.Config, record *TokenRecord) (string, error)
-}
-
 // Authenticator manages login and optional refresh flows for a provider.
 type Authenticator interface {
 	Provider() string
-	Login(ctx context.Context, cfg *config.Config, opts *LoginOptions) (*TokenRecord, error)
+	Login(ctx context.Context, cfg *config.Config, opts *LoginOptions) (*coreauth.Auth, error)
 	RefreshLead() *time.Duration
 }