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/channel/gemini/relay-gemini-native.go

@@ -5,6 +5,7 @@ import (
 	"net/http"
 	"one-api/common"
 	"one-api/dto"
+	"one-api/logger"
 	relaycommon "one-api/relay/common"
 	"one-api/relay/helper"
 	"one-api/service"
@@ -17,7 +18,7 @@ import (
 )
 
 func GeminiTextGenerationHandler(c *gin.Context, info *relaycommon.RelayInfo, resp *http.Response) (*dto.Usage, *types.NewAPIError) {
-	defer common.CloseResponseBodyGracefully(resp)
+	defer service.CloseResponseBodyGracefully(resp)
 
 	// 读取响应体
 	responseBody, err := io.ReadAll(resp.Body)
@@ -53,13 +54,13 @@ func GeminiTextGenerationHandler(c *gin.Context, info *relaycommon.RelayInfo, re
 		}
 	}
 
-	common.IOCopyBytesGracefully(c, resp, responseBody)
+	service.IOCopyBytesGracefully(c, resp, responseBody)
 
 	return &usage, nil
 }
 
 func NativeGeminiEmbeddingHandler(c *gin.Context, resp *http.Response, info *relaycommon.RelayInfo) (*dto.Usage, *types.NewAPIError) {
-	defer common.CloseResponseBodyGracefully(resp)
+	defer service.CloseResponseBodyGracefully(resp)
 
 	responseBody, err := io.ReadAll(resp.Body)
 	if err != nil {
@@ -89,7 +90,7 @@ func NativeGeminiEmbeddingHandler(c *gin.Context, resp *http.Response, info *rel
 		}
 	}
 
-	common.IOCopyBytesGracefully(c, resp, responseBody)
+	service.IOCopyBytesGracefully(c, resp, responseBody)
 
 	return usage, nil
 }
@@ -106,7 +107,7 @@ func GeminiTextGenerationStreamHandler(c *gin.Context, info *relaycommon.RelayIn
 		var geminiResponse dto.GeminiChatResponse
 		err := common.UnmarshalJsonStr(data, &geminiResponse)
 		if err != nil {
-			common.LogError(c, "error unmarshalling stream response: "+err.Error())
+			logger.LogError(c, "error unmarshalling stream response: "+err.Error())
 			return false
 		}
 
@@ -140,7 +141,7 @@ func GeminiTextGenerationStreamHandler(c *gin.Context, info *relaycommon.RelayIn
 		// 直接发送 GeminiChatResponse 响应
 		err = helper.StringData(c, data)
 		if err != nil {
-			common.LogError(c, err.Error())
+			logger.LogError(c, err.Error())
 		}
 		info.SendResponseCount++
 		return true