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`).

dto/claude.go

@@ -3,6 +3,7 @@ package dto
 import (
 	"encoding/json"
 	"one-api/common"
+	"one-api/types"
 )
 
 type ClaudeMetadata struct {
@@ -228,7 +229,7 @@ type ClaudeResponse struct {
 	Completion   string               `json:"completion,omitempty"`
 	StopReason   string               `json:"stop_reason,omitempty"`
 	Model        string               `json:"model,omitempty"`
-	Error        *ClaudeError         `json:"error,omitempty"`
+	Error        *types.ClaudeError   `json:"error,omitempty"`
 	Usage        *ClaudeUsage         `json:"usage,omitempty"`
 	Index        *int                 `json:"index,omitempty"`
 	ContentBlock *ClaudeMediaMessage  `json:"content_block,omitempty"`