refactor(auth): remove unused Refresh methods from authenticators

- Deleted `Refresh` implementations in Codex, Claude, Gemini, Qwen, and Gemini-web authenticators.
- Updated the `Authenticator` interface to exclude `Refresh` for cleaner design.
- Revised `Manager` and related components to handle refresh logic improvements.
- Simplified token refresh behavior and eliminated redundant code paths.

sdk/auth/interfaces.go

@@ -37,6 +37,5 @@ type TokenStore interface {
 type Authenticator interface {
 	Provider() string
 	Login(ctx context.Context, cfg *config.Config, opts *LoginOptions) (*TokenRecord, error)
-	Refresh(ctx context.Context, cfg *config.Config, record *TokenRecord) (*TokenRecord, error)
 	RefreshLead() *time.Duration
 }