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/service.go

@@ -0,0 +1,160 @@
+package apikey
+
+import (
+	"encoding/json"
+	"errors"
+	"time"
+
+	"go.uber.org/zap"
+	"gorm.io/gorm"
+
+	"openteam/server/internal/pkg/crypto"
+	"openteam/server/internal/pkg/rand"
+	"openteam/server/internal/store"
+)
+
+var ErrKeyNotFound = errors.New("api key not found")
+
+type Service struct {
+	db  *gorm.DB
+	log *zap.Logger
+}
+
+func NewService(db *gorm.DB, log *zap.Logger) *Service {
+	return &Service{db: db, log: log}
+}
+
+type CreateInput struct {
+	Name                string   `json:"name" binding:"required,max=128"`
+	QuotaTokensPerDay   *int64   `json:"quotaTokensPerDay"`
+	QuotaRequestsPerDay *int     `json:"quotaRequestsPerDay"`
+	AllowedModels       []string `json:"allowedModels"`
+	ExpiresInDays       *int     `json:"expiresInDays"`
+}
+
+type UpdateInput struct {
+	Name                *string  `json:"name"`
+	QuotaTokensPerDay   *int64   `json:"quotaTokensPerDay"`
+	QuotaRequestsPerDay *int     `json:"quotaRequestsPerDay"`
+	AllowedModels       []string `json:"allowedModels"`
+	ExpiresAt           *time.Time `json:"expiresAt"`
+	Status              *string  `json:"status"`
+}
+
+// Create generates a key and returns it once along with the stored record.
+func (s *Service) Create(userID int64, in CreateInput) (*store.ApiKey, string, error) {
+	plain, err := rand.Base62(48)
+	if err != nil {
+		return nil, "", err
+	}
+	full := "sk-" + plain
+	rec := &store.ApiKey{
+		UserID:              userID,
+		Name:                in.Name,
+		KeyHash:             crypto.HashSHA256(full),
+		KeyPrefix:           "sk-" + plain[:8],
+		QuotaTokensPerDay:   in.QuotaTokensPerDay,
+		QuotaRequestsPerDay: in.QuotaRequestsPerDay,
+		AllowedModels:       in.AllowedModels,
+		Status:              "active",
+	}
+	if in.ExpiresInDays != nil && *in.ExpiresInDays > 0 {
+		t := time.Now().AddDate(0, 0, *in.ExpiresInDays)
+		rec.ExpiresAt = &t
+	}
+	if err := s.db.Create(rec).Error; err != nil {
+		return nil, "", err
+	}
+	return rec, full, nil
+}
+
+// List returns the user's keys (never the hash).
+func (s *Service) List(userID int64) ([]store.ApiKey, error) {
+	var keys []store.ApiKey
+	err := s.db.Where("user_id = ?", userID).Order("id DESC").Find(&keys).Error
+	return keys, err
+}
+
+// Update patches a key owned by the user.
+func (s *Service) Update(userID, keyID int64, in UpdateInput) (*store.ApiKey, error) {
+	var k store.ApiKey
+	if err := s.db.First(&k, "id = ? AND user_id = ?", keyID, userID).Error; err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return nil, ErrKeyNotFound
+		}
+		return nil, err
+	}
+	updates := map[string]any{}
+	if in.Name != nil {
+		updates["name"] = *in.Name
+	}
+	if in.QuotaTokensPerDay != nil {
+		updates["quota_tokens_per_day"] = *in.QuotaTokensPerDay
+	}
+	if in.QuotaRequestsPerDay != nil {
+		updates["quota_requests_per_day"] = *in.QuotaRequestsPerDay
+	}
+	if in.AllowedModels != nil {
+		// GORM map updates skip the json serializer, so encode explicitly.
+		modelsJSON, err := json.Marshal(in.AllowedModels)
+		if err != nil {
+			return nil, err
+		}
+		updates["allowed_models"] = string(modelsJSON)
+	}
+	if in.ExpiresAt != nil {
+		updates["expires_at"] = in.ExpiresAt
+	}
+	if in.Status != nil {
+		updates["status"] = *in.Status
+	}
+	if len(updates) > 0 {
+		if err := s.db.Model(&k).Updates(updates).Error; err != nil {
+			return nil, err
+		}
+	}
+	return s.Get(userID, keyID)
+}
+
+// Delete revokes a key (soft revoke by status).
+func (s *Service) Delete(userID, keyID int64) error {
+	res := s.db.Model(&store.ApiKey{}).
+		Where("id = ? AND user_id = ?", keyID, userID).
+		Update("status", "revoked")
+	if res.Error != nil {
+		return res.Error
+	}
+	if res.RowsAffected == 0 {
+		return ErrKeyNotFound
+	}
+	return nil
+}
+
+// Get loads one key owned by the user.
+func (s *Service) Get(userID, keyID int64) (*store.ApiKey, error) {
+	var k store.ApiKey
+	if err := s.db.First(&k, "id = ? AND user_id = ?", keyID, userID).Error; err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return nil, ErrKeyNotFound
+		}
+		return nil, err
+	}
+	return &k, nil
+}
+
+// Public returns a DTO without the hash.
+func Public(k *store.ApiKey) map[string]any {
+	return map[string]any{
+		"id":                 k.ID,
+		"userId":             k.UserID,
+		"name":               k.Name,
+		"keyPrefix":          k.KeyPrefix,
+		"quotaTokensPerDay":  k.QuotaTokensPerDay,
+		"quotaRequestsPerDay": k.QuotaRequestsPerDay,
+		"allowedModels":      k.AllowedModels,
+		"expiresAt":          k.ExpiresAt,
+		"status":             k.Status,
+		"lastUsedAt":         k.LastUsedAt,
+		"createdAt":          k.CreatedAt,
+	}
+}