refactor(gemini-web): Remove auto-refresh, auto-close, and caching

This commit simplifies the Gemini web client by removing several complex, stateful features. The previous implementation for auto-refreshing cookies and auto-closing the client involved background goroutines, timers, and file system caching, which made the client's lifecycle difficult to manage.

The following features have been removed:
- The cookie auto-refresh mechanism, including the background goroutine (`rotateCookies`) and related configuration fields.
- The file-based caching for the `__Secure-1PSIDTS` token. The `rotate1PSIDTS` function now fetches a new token on every call.
- The auto-close functionality, which used timers to close the client after a period of inactivity.
- Associated configuration options and methods (`WithAccountLabel`, `WithOnCookiesRefreshed`, `Close`, etc.).

By removing this logic, the client becomes more stateless and predictable. The responsibility for managing the client's lifecycle and handling token expiration is now shifted to the caller, leading to a simpler and more robust integration.

internal/auth/gemini/gemini-web_token.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"time"
 
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/misc"
 	log "github.com/sirupsen/logrus"
@@ -18,12 +19,16 @@ type GeminiWebTokenStorage struct {
 	Secure1PSID   string `json:"secure_1psid"`
 	Secure1PSIDTS string `json:"secure_1psidts"`
 	Type          string `json:"type"`
+	LastRefresh   string `json:"last_refresh,omitempty"`
 }
 
 // SaveTokenToFile serializes the Gemini Web token storage to a JSON file.
 func (ts *GeminiWebTokenStorage) SaveTokenToFile(authFilePath string) error {
 	misc.LogSavingCredentials(authFilePath)
 	ts.Type = "gemini-web"
+	if ts.LastRefresh == "" {
+		ts.LastRefresh = time.Now().Format(time.RFC3339)
+	}
 	if err := os.MkdirAll(filepath.Dir(authFilePath), 0700); err != nil {
 		return fmt.Errorf("failed to create directory: %v", err)
 	}