refactor: Introduce pre-consume quota and unify relay handlers

This commit introduces a major architectural refactoring to improve quota management, centralize logging, and streamline the relay handling logic.

Key changes:
- **Pre-consume Quota:** Implements a new mechanism to check and reserve user quota *before* making the request to the upstream provider. This ensures more accurate quota deduction and prevents users from exceeding their limits due to concurrent requests.

- **Unified Relay Handlers:** Refactors the relay logic to use generic handlers (e.g., `ChatHandler`, `ImageHandler`) instead of provider-specific implementations. This significantly reduces code duplication and simplifies adding new channels.

- **Centralized Logger:** A new dedicated `logger` package is introduced, and all system logging calls are migrated to use it, moving this responsibility out of the `common` package.

- **Code Reorganization:** DTOs are generalized (e.g., `dalle.go` -> `openai_image.go`) and utility code is moved to more appropriate packages (e.g., `common/http.go` -> `service/http.go`) for better code structure.

service/cf_worker.go

@@ -5,7 +5,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"net/http"
-	"one-api/common"
+	"one-api/logger"
 	"one-api/setting"
 	"strings"
 )
@@ -44,14 +44,14 @@ func DoWorkerRequest(req *WorkerRequest) (*http.Response, error) {
 
 func DoDownloadRequest(originUrl string) (resp *http.Response, err error) {
 	if setting.EnableWorker() {
-		common.SysLog(fmt.Sprintf("downloading file from worker: %s", originUrl))
+		logger.SysLog(fmt.Sprintf("downloading file from worker: %s", originUrl))
 		req := &WorkerRequest{
 			URL: originUrl,
 			Key: setting.WorkerValidKey,
 		}
 		return DoWorkerRequest(req)
 	} else {
-		common.SysLog(fmt.Sprintf("downloading from origin: %s", originUrl))
+		logger.SysLog(fmt.Sprintf("downloading from origin: %s", originUrl))
 		return http.Get(originUrl)
 	}
 }