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.

logger/logger.go

@@ -0,0 +1,115 @@
+package logger
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"github.com/bytedance/gopkg/util/gopool"
+	"github.com/gin-gonic/gin"
+	"io"
+	"log"
+	"one-api/common"
+	"os"
+	"path/filepath"
+	"sync"
+	"time"
+)
+
+const (
+	loggerINFO  = "INFO"
+	loggerWarn  = "WARN"
+	loggerError = "ERR"
+	loggerDebug = "DEBUG"
+)
+
+const maxLogCount = 1000000
+
+var logCount int
+var setupLogLock sync.Mutex
+var setupLogWorking bool
+
+func SetupLogger() {
+	if *common.LogDir != "" {
+		ok := setupLogLock.TryLock()
+		if !ok {
+			log.Println("setup log is already working")
+			return
+		}
+		defer func() {
+			setupLogLock.Unlock()
+			setupLogWorking = false
+		}()
+		logPath := filepath.Join(*common.LogDir, fmt.Sprintf("oneapi-%s.log", time.Now().Format("20060102150405")))
+		fd, err := os.OpenFile(logPath, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
+		if err != nil {
+			log.Fatal("failed to open log file")
+		}
+		gin.DefaultWriter = io.MultiWriter(os.Stdout, fd)
+		gin.DefaultErrorWriter = io.MultiWriter(os.Stderr, fd)
+	}
+}
+
+func LogInfo(ctx context.Context, msg string) {
+	logHelper(ctx, loggerINFO, msg)
+}
+
+func LogWarn(ctx context.Context, msg string) {
+	logHelper(ctx, loggerWarn, msg)
+}
+
+func LogError(ctx context.Context, msg string) {
+	logHelper(ctx, loggerError, msg)
+}
+
+func LogDebug(ctx context.Context, msg string) {
+	if common.DebugEnabled {
+		logHelper(ctx, loggerDebug, msg)
+	}
+}
+
+func logHelper(ctx context.Context, level string, msg string) {
+	writer := gin.DefaultErrorWriter
+	if level == loggerINFO {
+		writer = gin.DefaultWriter
+	}
+	id := ctx.Value(common.RequestIdKey)
+	if id == nil {
+		id = "SYSTEM"
+	}
+	now := time.Now()
+	_, _ = fmt.Fprintf(writer, "[%s] %v | %s | %s \n", level, now.Format("2006/01/02 - 15:04:05"), id, msg)
+	logCount++ // we don't need accurate count, so no lock here
+	if logCount > maxLogCount && !setupLogWorking {
+		logCount = 0
+		setupLogWorking = true
+		gopool.Go(func() {
+			SetupLogger()
+		})
+	}
+}
+
+func LogQuota(quota int) string {
+	if common.DisplayInCurrencyEnabled {
+		return fmt.Sprintf("＄%.6f 额度", float64(quota)/common.QuotaPerUnit)
+	} else {
+		return fmt.Sprintf("%d 点额度", quota)
+	}
+}
+
+func FormatQuota(quota int) string {
+	if common.DisplayInCurrencyEnabled {
+		return fmt.Sprintf("＄%.6f", float64(quota)/common.QuotaPerUnit)
+	} else {
+		return fmt.Sprintf("%d", quota)
+	}
+}
+
+// LogJson 仅供测试使用 only for test
+func LogJson(ctx context.Context, msg string, obj any) {
+	jsonStr, err := json.Marshal(obj)
+	if err != nil {
+		LogError(ctx, fmt.Sprintf("json marshal failed: %s", err.Error()))
+		return
+	}
+	LogInfo(ctx, fmt.Sprintf("%s | %s", msg, string(jsonStr)))
+}