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.

middleware/turnstile-check.go

@@ -7,6 +7,7 @@ import (
 	"net/http"
 	"net/url"
 	"one-api/common"
+	"one-api/logger"
 )
 
 type turnstileCheckResponse struct {
@@ -37,7 +38,7 @@ func TurnstileCheck() gin.HandlerFunc {
 				"remoteip": {c.ClientIP()},
 			})
 			if err != nil {
-				common.SysError(err.Error())
+				logger.SysError(err.Error())
 				c.JSON(http.StatusOK, gin.H{
 					"success": false,
 					"message": err.Error(),
@@ -49,7 +50,7 @@ func TurnstileCheck() gin.HandlerFunc {
 			var res turnstileCheckResponse
 			err = json.NewDecoder(rawRes.Body).Decode(&res)
 			if err != nil {
-				common.SysError(err.Error())
+				logger.SysError(err.Error())
 				c.JSON(http.StatusOK, gin.H{
 					"success": false,
 					"message": err.Error(),