feat(server): API relay gateway backend M0-M4

Gin + GORM + pure-Go SQLite. Users/auth (JWT), API key management with
quotas, proxy gateway with weighted channel failover and health checks,
usage/billing ledger, cross-protocol conversion (Anthropic Messages /
OpenAI Chat Completions / OpenAI Responses), and channel/model admin API.
Channels declare native API formats and auto-convert the rest.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

server/internal/recharge/handler.go

@@ -0,0 +1,84 @@
+package recharge
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+	"github.com/shopspring/decimal"
+	"go.uber.org/zap"
+	"gorm.io/gorm"
+
+	"openteam/server/internal/pkg/httpx"
+	"openteam/server/internal/store"
+	"openteam/server/internal/user"
+)
+
+// Handler exposes the reserved recharge order endpoints.
+type Handler struct {
+	db  *gorm.DB
+	log *zap.Logger
+}
+
+func NewHandler(db *gorm.DB, log *zap.Logger) *Handler {
+	return &Handler{db: db, log: log}
+}
+
+type CreateInput struct {
+	Amount decimal.Decimal `json:"amount" binding:"required"`
+	Remark string          `json:"remark"`
+}
+
+// Create handles POST /api/v1/recharges — creates a pending manual order.
+func (h *Handler) Create(c *gin.Context) {
+	u := user.Current(c)
+	var in CreateInput
+	if !httpx.Bind(c, &in) {
+		return
+	}
+	if in.Amount.LessThanOrEqual(decimal.Zero) {
+		httpx.Fail(c, http.StatusBadRequest, "amount must be positive")
+		return
+	}
+	order := &store.RechargeOrder{
+		UserID: u.ID,
+		Amount: in.Amount,
+		Status: "pending",
+		Method: "manual",
+		Remark: in.Remark,
+	}
+	if err := h.db.Create(order).Error; err != nil {
+		h.log.Warn("create recharge order failed", zap.Error(err))
+		httpx.Fail(c, http.StatusInternalServerError, "create order failed")
+		return
+	}
+	httpx.Created(c, orderDTO(order))
+}
+
+// List handles GET /api/v1/recharges.
+func (h *Handler) List(c *gin.Context) {
+	u := user.Current(c)
+	var orders []store.RechargeOrder
+	if err := h.db.Where("user_id = ?", u.ID).Order("id DESC").Find(&orders).Error; err != nil {
+		h.log.Warn("list recharge orders failed", zap.Error(err))
+		httpx.Fail(c, http.StatusInternalServerError, "list orders failed")
+		return
+	}
+	out := make([]gin.H, 0, len(orders))
+	for i := range orders {
+		out = append(out, orderDTO(&orders[i]))
+	}
+	httpx.OK(c, out)
+}
+
+func orderDTO(o *store.RechargeOrder) gin.H {
+	return gin.H{
+		"id":          o.ID,
+		"amount":      o.Amount.String(),
+		"status":      o.Status,
+		"method":      o.Method,
+		"remark":      o.Remark,
+		"reviewedBy":  o.ReviewedBy,
+		"reviewedAt":  o.ReviewedAt,
+		"createdAt":   o.CreatedAt,
+	}
+}