refactor: Introduce standardized API error

This commit refactors the application's error handling mechanism by introducing a new standardized error type, `types.NewAPIError`. It also renames common JSON utility functions for better clarity.

Previously, internal error handling was tightly coupled to the `dto.OpenAIError` format. This change decouples the internal logic from the external API representation.

Key changes:
- A new `types.NewAPIError` struct is introduced to serve as a canonical internal representation for all API errors.
- All relay adapters (OpenAI, Claude, Gemini, etc.) are updated to return `*types.NewAPIError`.
- Controllers now convert the internal `NewAPIError` to the client-facing `OpenAIError` format at the API boundary, ensuring backward compatibility.
- Channel auto-disable/enable logic is updated to use the new standardized error type.
- JSON utility functions are renamed to align with Go's standard library conventions (e.g., `UnmarshalJson` -> `Unmarshal`, `EncodeJson` -> `Marshal`).

relay/helper/common.go

@@ -4,27 +4,29 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"github.com/gin-gonic/gin"
-	"github.com/gorilla/websocket"
 	"net/http"
 	"one-api/common"
 	"one-api/dto"
+	"one-api/types"
+
+	"github.com/gin-gonic/gin"
+	"github.com/gorilla/websocket"
 )
 
 func SetEventStreamHeaders(c *gin.Context) {
-    // 检查是否已经设置过头部
-    if _, exists := c.Get("event_stream_headers_set"); exists {
-        return
-    }
-    
-    c.Writer.Header().Set("Content-Type", "text/event-stream")
-    c.Writer.Header().Set("Cache-Control", "no-cache")
-    c.Writer.Header().Set("Connection", "keep-alive")
-    c.Writer.Header().Set("Transfer-Encoding", "chunked")
-    c.Writer.Header().Set("X-Accel-Buffering", "no")
-    
-    // 设置标志，表示头部已经设置过
-    c.Set("event_stream_headers_set", true)
+	// 检查是否已经设置过头部
+	if _, exists := c.Get("event_stream_headers_set"); exists {
+		return
+	}
+
+	c.Writer.Header().Set("Content-Type", "text/event-stream")
+	c.Writer.Header().Set("Cache-Control", "no-cache")
+	c.Writer.Header().Set("Connection", "keep-alive")
+	c.Writer.Header().Set("Transfer-Encoding", "chunked")
+	c.Writer.Header().Set("X-Accel-Buffering", "no")
+
+	// 设置标志，表示头部已经设置过
+	c.Set("event_stream_headers_set", true)
 }
 
 func ClaudeData(c *gin.Context, resp dto.ClaudeResponse) error {
@@ -85,7 +87,7 @@ func ObjectData(c *gin.Context, object interface{}) error {
 	if object == nil {
 		return errors.New("object is nil")
 	}
-	jsonData, err := json.Marshal(object)
+	jsonData, err := common.Marshal(object)
 	if err != nil {
 		return fmt.Errorf("error marshalling object: %w", err)
 	}
@@ -118,7 +120,7 @@ func WssObject(c *gin.Context, ws *websocket.Conn, object interface{}) error {
 	return ws.WriteMessage(1, jsonData)
 }
 
-func WssError(c *gin.Context, ws *websocket.Conn, openaiError dto.OpenAIError) {
+func WssError(c *gin.Context, ws *websocket.Conn, openaiError types.OpenAIError) {
 	errorObj := &dto.RealtimeEvent{
 		Type:    "error",
 		EventId: GetLocalRealtimeID(c),