M0-M4: 推倒重来基线(基建+用户/密钥/核心代理+前端+管理后台+三协议互转)

- 后端 Go+Gin+GORM: 配置(OT_ env)/SQLite/Postgres 双驱动、用户体系(argon2id+JWT access/refresh)、
  API Key(sk- 48位, 仅存 SHA-256 哈希)
- 代理网关: /v1/chat/completions、/v1/responses、/v1/messages、/v1/models;错误按客户端协议返回
- 三协议互转(convert 包): Chat↔Messages↔Responses 请求/响应 + 流式 SSE 逐事件转换(直通优先)
- 用量计费: 异步批量记账、余额扣减、balance_logs、usage_daily 日聚合
- 管理 API: 用户/渠道 CRUD+测试+模型导入/模型定价+绑定/统计/系统配置
- 前端 Vue3+TS+Tailwind(taste-skill 设计 tokens): Landing/登录注册/控制台/管理后台,
  自建组件+Phosphor 图标+自建 SVG 趋势图, 已过 web-design-guidelines 复查
- mock 上游: OpenAI+Anthropic 双协议模拟(含流式)

Co-Authored-By: Claude <noreply@anthropic.com>

server/internal/proxy/convert/convert.go

@@ -0,0 +1,157 @@
+// Package convert 三协议互转：OpenAI Chat / OpenAI Responses / Anthropic Messages。
+// 网关以 OpenAI Chat 形状作为标准中间模型（PLANNING §5.1.1）。
+// 请求与响应（非流式）走 JSON 转换；流式走逐行 SSE 转换（见 stream.go）。
+package convert
+
+import (
+	"encoding/json"
+	"fmt"
+)
+
+// 协议标识。
+const (
+	ProtoChat      = "chat"
+	ProtoMessages  = "messages"
+	ProtoResponses = "responses"
+)
+
+// ConvertRequest 转换请求体。from==to 时原样返回。
+func ConvertRequest(body []byte, from, to string) ([]byte, error) {
+	if from == to {
+		return body, nil
+	}
+	switch {
+	case from == ProtoMessages && to == ProtoChat:
+		return messagesToChatReq(body)
+	case from == ProtoChat && to == ProtoMessages:
+		return chatToMessagesReq(body)
+	case from == ProtoResponses && to == ProtoChat:
+		return responsesToChatReq(body)
+	case from == ProtoChat && to == ProtoResponses:
+		return chatToResponsesReq(body)
+	case from == ProtoResponses && to == ProtoMessages:
+		mid, err := responsesToChatReq(body)
+		if err != nil {
+			return nil, err
+		}
+		return chatToMessagesReq(mid)
+	case from == ProtoMessages && to == ProtoResponses:
+		mid, err := messagesToChatReq(body)
+		if err != nil {
+			return nil, err
+		}
+		return chatToResponsesReq(mid)
+	}
+	return nil, fmt.Errorf("unsupported request conversion %s->%s", from, to)
+}
+
+// ConvertResponse 转换响应体（非流式）。from==to 时原样返回。
+func ConvertResponse(body []byte, from, to string) ([]byte, error) {
+	if from == to {
+		return body, nil
+	}
+	switch {
+	case from == ProtoMessages && to == ProtoChat:
+		return messagesToChatResp(body)
+	case from == ProtoChat && to == ProtoMessages:
+		return chatToMessagesResp(body)
+	case from == ProtoResponses && to == ProtoChat:
+		return responsesToChatResp(body)
+	case from == ProtoChat && to == ProtoResponses:
+		return chatToResponsesResp(body)
+	case from == ProtoResponses && to == ProtoMessages:
+		mid, err := responsesToChatResp(body)
+		if err != nil {
+			return nil, err
+		}
+		return chatToMessagesResp(mid)
+	case from == ProtoMessages && to == ProtoResponses:
+		mid, err := messagesToChatResp(body)
+		if err != nil {
+			return nil, err
+		}
+		return chatToResponsesResp(mid)
+	}
+	return nil, fmt.Errorf("unsupported response conversion %s->%s", from, to)
+}
+
+// NewStreamTransformer 构造流式逐行转换器：输入上游 SSE 一行，返回客户端 SSE 行。
+// 返回 nil 表示丢弃该行；(from==to 时无需转换)。
+func NewStreamTransformer(from, to string) func([]byte) []byte {
+	switch {
+	case from == ProtoMessages && to == ProtoChat:
+		return newMessagesToChat().line
+	case from == ProtoChat && to == ProtoMessages:
+		return newChatToMessages().line
+	case from == ProtoResponses && to == ProtoChat:
+		return newResponsesToChat().line
+	case from == ProtoChat && to == ProtoResponses:
+		return newChatToResponses().line
+	case from == ProtoResponses && to == ProtoMessages:
+		return newResponsesToMessages().line
+	case from == ProtoMessages && to == ProtoResponses:
+		return newMessagesToResponses().line
+	}
+	return nil
+}
+
+// ---------------------------------------------------------------------------
+// 工具函数
+
+// str 返回字符串字段；json.RawMessage 为字符串字面量时去引号。
+func str(raw json.RawMessage) string {
+	if len(raw) == 0 || string(raw) == "null" {
+		return ""
+	}
+	var s string
+	if json.Unmarshal(raw, &s) == nil {
+		return s
+	}
+	// 数组/对象：尝试取 type=text 的 text
+	var arr []map[string]any
+	if json.Unmarshal(raw, &arr) == nil {
+		var parts []string
+		for _, b := range arr {
+			if t, _ := b["type"].(string); t == "text" || t == "input_text" || t == "output_text" {
+				if txt, _ := b["text"].(string); txt != "" {
+					parts = append(parts, txt)
+				}
+			}
+		}
+		return joinNonEmpty(parts, "\n")
+	}
+	return ""
+}
+
+func joinNonEmpty(parts []string, sep string) string {
+	out := ""
+	for i, p := range parts {
+		if p == "" {
+			continue
+		}
+		if out != "" {
+			out += sep
+		}
+		out += p
+		_ = i
+	}
+	return out
+}
+
+// rawJSON 安全取字段；不存在或 null 返回 nil。
+func rawJSON(m map[string]json.RawMessage, key string) json.RawMessage {
+	raw, ok := m[key]
+	if !ok || string(raw) == "null" {
+		return nil
+	}
+	return raw
+}
+
+// decode 把 RawMessage 解到 map。
+func decode(raw json.RawMessage) (map[string]any, error) {
+	var m map[string]any
+	if err := json.Unmarshal(raw, &m); err != nil {
+		return nil, err
+	}
+	return m, nil
+}