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.

relay/helper/common.go

@@ -7,6 +7,7 @@ import (
 	"net/http"
 	"one-api/common"
 	"one-api/dto"
+	"one-api/logger"
 	"one-api/types"
 
 	"github.com/gin-gonic/gin"
@@ -100,7 +101,7 @@ func Done(c *gin.Context) {
 
 func WssString(c *gin.Context, ws *websocket.Conn, str string) error {
 	if ws == nil {
-		common.LogError(c, "websocket connection is nil")
+		logger.LogError(c, "websocket connection is nil")
 		return errors.New("websocket connection is nil")
 	}
 	//common.LogInfo(c, fmt.Sprintf("sending message: %s", str))
@@ -113,7 +114,7 @@ func WssObject(c *gin.Context, ws *websocket.Conn, object interface{}) error {
 		return fmt.Errorf("error marshalling object: %w", err)
 	}
 	if ws == nil {
-		common.LogError(c, "websocket connection is nil")
+		logger.LogError(c, "websocket connection is nil")
 		return errors.New("websocket connection is nil")
 	}
 	//common.LogInfo(c, fmt.Sprintf("sending message: %s", jsonData))