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/apikey/handler.go

@@ -0,0 +1,99 @@
+package apikey
+
+import (
+	"errors"
+	"net/http"
+	"strconv"
+
+	"github.com/gin-gonic/gin"
+	"go.uber.org/zap"
+
+	"openteam/server/internal/pkg/httpx"
+	"openteam/server/internal/user"
+)
+
+type Handler struct {
+	svc *Service
+	log *zap.Logger
+}
+
+func NewHandler(svc *Service, log *zap.Logger) *Handler {
+	return &Handler{svc: svc, log: log}
+}
+
+// List handles GET /api/v1/keys.
+func (h *Handler) List(c *gin.Context) {
+	u := user.Current(c)
+	keys, err := h.svc.List(u.ID)
+	if err != nil {
+		h.log.Warn("list keys failed", zap.Error(err))
+		httpx.Fail(c, http.StatusInternalServerError, "list keys failed")
+		return
+	}
+	out := make([]map[string]any, 0, len(keys))
+	for i := range keys {
+		out = append(out, Public(&keys[i]))
+	}
+	httpx.OK(c, out)
+}
+
+// Create handles POST /api/v1/keys.
+func (h *Handler) Create(c *gin.Context) {
+	u := user.Current(c)
+	var in CreateInput
+	if !httpx.Bind(c, &in) {
+		return
+	}
+	rec, plain, err := h.svc.Create(u.ID, in)
+	if err != nil {
+		h.log.Warn("create key failed", zap.Error(err))
+		httpx.Fail(c, http.StatusInternalServerError, "create key failed")
+		return
+	}
+	data := Public(rec)
+	data["key"] = plain // shown only once
+	httpx.Created(c, data)
+}
+
+// Update handles PATCH /api/v1/keys/:id.
+func (h *Handler) Update(c *gin.Context) {
+	u := user.Current(c)
+	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		httpx.Fail(c, http.StatusBadRequest, "invalid key id")
+		return
+	}
+	var in UpdateInput
+	if !httpx.Bind(c, &in) {
+		return
+	}
+	rec, err := h.svc.Update(u.ID, id, in)
+	if err != nil {
+		if errors.Is(err, ErrKeyNotFound) {
+			httpx.Fail(c, http.StatusNotFound, "api key not found")
+			return
+		}
+		httpx.Fail(c, http.StatusInternalServerError, "update key failed")
+		return
+	}
+	httpx.OK(c, Public(rec))
+}
+
+// Delete handles DELETE /api/v1/keys/:id.
+func (h *Handler) Delete(c *gin.Context) {
+	u := user.Current(c)
+	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		httpx.Fail(c, http.StatusBadRequest, "invalid key id")
+		return
+	}
+	if err := h.svc.Delete(u.ID, id); err != nil {
+		if errors.Is(err, ErrKeyNotFound) {
+			httpx.Fail(c, http.StatusNotFound, "api key not found")
+			return
+		}
+		httpx.Fail(c, http.StatusInternalServerError, "revoke key failed")
+		return
+	}
+	httpx.OK(c, gin.H{"ok": true})
+}