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.

model/user_cache.go

@@ -5,6 +5,7 @@ import (
 	"one-api/common"
 	"one-api/constant"
 	"one-api/dto"
+	"one-api/logger"
 	"time"
 
 	"github.com/gin-gonic/gin"
@@ -37,7 +38,7 @@ func (user *UserBase) GetSetting() dto.UserSetting {
 	if user.Setting != "" {
 		err := common.Unmarshal([]byte(user.Setting), &setting)
 		if err != nil {
-			common.SysError("failed to unmarshal setting: " + err.Error())
+			logger.SysError("failed to unmarshal setting: " + err.Error())
 		}
 	}
 	return setting
@@ -78,7 +79,7 @@ func GetUserCache(userId int) (userCache *UserBase, err error) {
 		if shouldUpdateRedis(fromDB, err) && user != nil {
 			gopool.Go(func() {
 				if err := updateUserCache(*user); err != nil {
-					common.SysError("failed to update user status cache: " + err.Error())
+					logger.SysError("failed to update user status cache: " + err.Error())
 				}
 			})
 		}