feat(groups): add Claude Code client restriction and session isolation

- Add claude_code_only field to restrict groups to Claude Code clients only
- Add fallback_group_id for non-Claude Code requests to use alternate group
- Implement ClaudeCodeValidator for User-Agent detection
- Add group-level session binding isolation (groupID in Redis key)
- Prevent cross-group sticky session pollution
- Update frontend with Claude Code restriction controls

backend/ent/group.go

@@ -51,6 +51,10 @@ type Group struct {
 	ImagePrice2k *float64 `json:"image_price_2k,omitempty"`
 	// ImagePrice4k holds the value of the "image_price_4k" field.
 	ImagePrice4k *float64 `json:"image_price_4k,omitempty"`
+	// 是否仅允许 Claude Code 客户端
+	ClaudeCodeOnly bool `json:"claude_code_only,omitempty"`
+	// 非 Claude Code 请求降级使用的分组 ID
+	FallbackGroupID *int64 `json:"fallback_group_id,omitempty"`
 	// Edges holds the relations/edges for other nodes in the graph.
 	// The values are being populated by the GroupQuery when eager-loading is set.
 	Edges        GroupEdges `json:"edges"`
@@ -157,11 +161,11 @@ func (*Group) scanValues(columns []string) ([]any, error) {
 	values := make([]any, len(columns))
 	for i := range columns {
 		switch columns[i] {
-		case group.FieldIsExclusive:
+		case group.FieldIsExclusive, group.FieldClaudeCodeOnly:
 			values[i] = new(sql.NullBool)
 		case group.FieldRateMultiplier, group.FieldDailyLimitUsd, group.FieldWeeklyLimitUsd, group.FieldMonthlyLimitUsd, group.FieldImagePrice1k, group.FieldImagePrice2k, group.FieldImagePrice4k:
 			values[i] = new(sql.NullFloat64)
-		case group.FieldID, group.FieldDefaultValidityDays:
+		case group.FieldID, group.FieldDefaultValidityDays, group.FieldFallbackGroupID:
 			values[i] = new(sql.NullInt64)
 		case group.FieldName, group.FieldDescription, group.FieldStatus, group.FieldPlatform, group.FieldSubscriptionType:
 			values[i] = new(sql.NullString)
@@ -298,6 +302,19 @@ func (_m *Group) assignValues(columns []string, values []any) error {
 				_m.ImagePrice4k = new(float64)
 				*_m.ImagePrice4k = value.Float64
 			}
+		case group.FieldClaudeCodeOnly:
+			if value, ok := values[i].(*sql.NullBool); !ok {
+				return fmt.Errorf("unexpected type %T for field claude_code_only", values[i])
+			} else if value.Valid {
+				_m.ClaudeCodeOnly = value.Bool
+			}
+		case group.FieldFallbackGroupID:
+			if value, ok := values[i].(*sql.NullInt64); !ok {
+				return fmt.Errorf("unexpected type %T for field fallback_group_id", values[i])
+			} else if value.Valid {
+				_m.FallbackGroupID = new(int64)
+				*_m.FallbackGroupID = value.Int64
+			}
 		default:
 			_m.selectValues.Set(columns[i], values[i])
 		}
@@ -440,6 +457,14 @@ func (_m *Group) String() string {
 		builder.WriteString("image_price_4k=")
 		builder.WriteString(fmt.Sprintf("%v", *v))
 	}
+	builder.WriteString(", ")
+	builder.WriteString("claude_code_only=")
+	builder.WriteString(fmt.Sprintf("%v", _m.ClaudeCodeOnly))
+	builder.WriteString(", ")
+	if v := _m.FallbackGroupID; v != nil {
+		builder.WriteString("fallback_group_id=")
+		builder.WriteString(fmt.Sprintf("%v", *v))
+	}
 	builder.WriteByte(')')
 	return builder.String()
 }

backend/ent/group/group.go

@@ -49,6 +49,10 @@ const (
 	FieldImagePrice2k = "image_price_2k"
 	// FieldImagePrice4k holds the string denoting the image_price_4k field in the database.
 	FieldImagePrice4k = "image_price_4k"
+	// FieldClaudeCodeOnly holds the string denoting the claude_code_only field in the database.
+	FieldClaudeCodeOnly = "claude_code_only"
+	// FieldFallbackGroupID holds the string denoting the fallback_group_id field in the database.
+	FieldFallbackGroupID = "fallback_group_id"
 	// EdgeAPIKeys holds the string denoting the api_keys edge name in mutations.
 	EdgeAPIKeys = "api_keys"
 	// EdgeRedeemCodes holds the string denoting the redeem_codes edge name in mutations.
@@ -141,6 +145,8 @@ var Columns = []string{
 	FieldImagePrice1k,
 	FieldImagePrice2k,
 	FieldImagePrice4k,
+	FieldClaudeCodeOnly,
+	FieldFallbackGroupID,
 }
 
 var (
@@ -196,6 +202,8 @@ var (
 	SubscriptionTypeValidator func(string) error
 	// DefaultDefaultValidityDays holds the default value on creation for the "default_validity_days" field.
 	DefaultDefaultValidityDays int
+	// DefaultClaudeCodeOnly holds the default value on creation for the "claude_code_only" field.
+	DefaultClaudeCodeOnly bool
 )
 
 // OrderOption defines the ordering options for the Group queries.
@@ -291,6 +299,16 @@ func ByImagePrice4k(opts ...sql.OrderTermOption) OrderOption {
 	return sql.OrderByField(FieldImagePrice4k, opts...).ToFunc()
 }
 
+// ByClaudeCodeOnly orders the results by the claude_code_only field.
+func ByClaudeCodeOnly(opts ...sql.OrderTermOption) OrderOption {
+	return sql.OrderByField(FieldClaudeCodeOnly, opts...).ToFunc()
+}
+
+// ByFallbackGroupID orders the results by the fallback_group_id field.
+func ByFallbackGroupID(opts ...sql.OrderTermOption) OrderOption {
+	return sql.OrderByField(FieldFallbackGroupID, opts...).ToFunc()
+}
+
 // ByAPIKeysCount orders the results by api_keys count.
 func ByAPIKeysCount(opts ...sql.OrderTermOption) OrderOption {
 	return func(s *sql.Selector) {

backend/ent/group/where.go

@@ -140,6 +140,16 @@ func ImagePrice4k(v float64) predicate.Group {
 	return predicate.Group(sql.FieldEQ(FieldImagePrice4k, v))
 }
 
+// ClaudeCodeOnly applies equality check predicate on the "claude_code_only" field. It's identical to ClaudeCodeOnlyEQ.
+func ClaudeCodeOnly(v bool) predicate.Group {
+	return predicate.Group(sql.FieldEQ(FieldClaudeCodeOnly, v))
+}
+
+// FallbackGroupID applies equality check predicate on the "fallback_group_id" field. It's identical to FallbackGroupIDEQ.
+func FallbackGroupID(v int64) predicate.Group {
+	return predicate.Group(sql.FieldEQ(FieldFallbackGroupID, v))
+}
+
 // CreatedAtEQ applies the EQ predicate on the "created_at" field.
 func CreatedAtEQ(v time.Time) predicate.Group {
 	return predicate.Group(sql.FieldEQ(FieldCreatedAt, v))
@@ -995,6 +1005,66 @@ func ImagePrice4kNotNil() predicate.Group {
 	return predicate.Group(sql.FieldNotNull(FieldImagePrice4k))
 }
 
+// ClaudeCodeOnlyEQ applies the EQ predicate on the "claude_code_only" field.
+func ClaudeCodeOnlyEQ(v bool) predicate.Group {
+	return predicate.Group(sql.FieldEQ(FieldClaudeCodeOnly, v))
+}
+
+// ClaudeCodeOnlyNEQ applies the NEQ predicate on the "claude_code_only" field.
+func ClaudeCodeOnlyNEQ(v bool) predicate.Group {
+	return predicate.Group(sql.FieldNEQ(FieldClaudeCodeOnly, v))
+}
+
+// FallbackGroupIDEQ applies the EQ predicate on the "fallback_group_id" field.
+func FallbackGroupIDEQ(v int64) predicate.Group {
+	return predicate.Group(sql.FieldEQ(FieldFallbackGroupID, v))
+}
+
+// FallbackGroupIDNEQ applies the NEQ predicate on the "fallback_group_id" field.
+func FallbackGroupIDNEQ(v int64) predicate.Group {
+	return predicate.Group(sql.FieldNEQ(FieldFallbackGroupID, v))
+}
+
+// FallbackGroupIDIn applies the In predicate on the "fallback_group_id" field.
+func FallbackGroupIDIn(vs ...int64) predicate.Group {
+	return predicate.Group(sql.FieldIn(FieldFallbackGroupID, vs...))
+}
+
+// FallbackGroupIDNotIn applies the NotIn predicate on the "fallback_group_id" field.
+func FallbackGroupIDNotIn(vs ...int64) predicate.Group {
+	return predicate.Group(sql.FieldNotIn(FieldFallbackGroupID, vs...))
+}
+
+// FallbackGroupIDGT applies the GT predicate on the "fallback_group_id" field.
+func FallbackGroupIDGT(v int64) predicate.Group {
+	return predicate.Group(sql.FieldGT(FieldFallbackGroupID, v))
+}
+
+// FallbackGroupIDGTE applies the GTE predicate on the "fallback_group_id" field.
+func FallbackGroupIDGTE(v int64) predicate.Group {
+	return predicate.Group(sql.FieldGTE(FieldFallbackGroupID, v))
+}
+
+// FallbackGroupIDLT applies the LT predicate on the "fallback_group_id" field.
+func FallbackGroupIDLT(v int64) predicate.Group {
+	return predicate.Group(sql.FieldLT(FieldFallbackGroupID, v))
+}
+
+// FallbackGroupIDLTE applies the LTE predicate on the "fallback_group_id" field.
+func FallbackGroupIDLTE(v int64) predicate.Group {
+	return predicate.Group(sql.FieldLTE(FieldFallbackGroupID, v))
+}
+
+// FallbackGroupIDIsNil applies the IsNil predicate on the "fallback_group_id" field.
+func FallbackGroupIDIsNil() predicate.Group {
+	return predicate.Group(sql.FieldIsNull(FieldFallbackGroupID))
+}
+
+// FallbackGroupIDNotNil applies the NotNil predicate on the "fallback_group_id" field.
+func FallbackGroupIDNotNil() predicate.Group {
+	return predicate.Group(sql.FieldNotNull(FieldFallbackGroupID))
+}
+
 // HasAPIKeys applies the HasEdge predicate on the "api_keys" edge.
 func HasAPIKeys() predicate.Group {
 	return predicate.Group(func(s *sql.Selector) {

backend/ent/group_create.go

@@ -258,6 +258,34 @@ func (_c *GroupCreate) SetNillableImagePrice4k(v *float64) *GroupCreate {
 	return _c
 }
 
+// SetClaudeCodeOnly sets the "claude_code_only" field.
+func (_c *GroupCreate) SetClaudeCodeOnly(v bool) *GroupCreate {
+	_c.mutation.SetClaudeCodeOnly(v)
+	return _c
+}
+
+// SetNillableClaudeCodeOnly sets the "claude_code_only" field if the given value is not nil.
+func (_c *GroupCreate) SetNillableClaudeCodeOnly(v *bool) *GroupCreate {
+	if v != nil {
+		_c.SetClaudeCodeOnly(*v)
+	}
+	return _c
+}
+
+// SetFallbackGroupID sets the "fallback_group_id" field.
+func (_c *GroupCreate) SetFallbackGroupID(v int64) *GroupCreate {
+	_c.mutation.SetFallbackGroupID(v)
+	return _c
+}
+
+// SetNillableFallbackGroupID sets the "fallback_group_id" field if the given value is not nil.
+func (_c *GroupCreate) SetNillableFallbackGroupID(v *int64) *GroupCreate {
+	if v != nil {
+		_c.SetFallbackGroupID(*v)
+	}
+	return _c
+}
+
 // AddAPIKeyIDs adds the "api_keys" edge to the APIKey entity by IDs.
 func (_c *GroupCreate) AddAPIKeyIDs(ids ...int64) *GroupCreate {
 	_c.mutation.AddAPIKeyIDs(ids...)
@@ -423,6 +451,10 @@ func (_c *GroupCreate) defaults() error {
 		v := group.DefaultDefaultValidityDays
 		_c.mutation.SetDefaultValidityDays(v)
 	}
+	if _, ok := _c.mutation.ClaudeCodeOnly(); !ok {
+		v := group.DefaultClaudeCodeOnly
+		_c.mutation.SetClaudeCodeOnly(v)
+	}
 	return nil
 }
 
@@ -475,6 +507,9 @@ func (_c *GroupCreate) check() error {
 	if _, ok := _c.mutation.DefaultValidityDays(); !ok {
 		return &ValidationError{Name: "default_validity_days", err: errors.New(`ent: missing required field "Group.default_validity_days"`)}
 	}
+	if _, ok := _c.mutation.ClaudeCodeOnly(); !ok {
+		return &ValidationError{Name: "claude_code_only", err: errors.New(`ent: missing required field "Group.claude_code_only"`)}
+	}
 	return nil
 }
 
@@ -570,6 +605,14 @@ func (_c *GroupCreate) createSpec() (*Group, *sqlgraph.CreateSpec) {
 		_spec.SetField(group.FieldImagePrice4k, field.TypeFloat64, value)
 		_node.ImagePrice4k = &value
 	}
+	if value, ok := _c.mutation.ClaudeCodeOnly(); ok {
+		_spec.SetField(group.FieldClaudeCodeOnly, field.TypeBool, value)
+		_node.ClaudeCodeOnly = value
+	}
+	if value, ok := _c.mutation.FallbackGroupID(); ok {
+		_spec.SetField(group.FieldFallbackGroupID, field.TypeInt64, value)
+		_node.FallbackGroupID = &value
+	}
 	if nodes := _c.mutation.APIKeysIDs(); len(nodes) > 0 {
 		edge := &sqlgraph.EdgeSpec{
 			Rel:     sqlgraph.O2M,
@@ -1014,6 +1057,42 @@ func (u *GroupUpsert) ClearImagePrice4k() *GroupUpsert {
 	return u
 }
 
+// SetClaudeCodeOnly sets the "claude_code_only" field.
+func (u *GroupUpsert) SetClaudeCodeOnly(v bool) *GroupUpsert {
+	u.Set(group.FieldClaudeCodeOnly, v)
+	return u
+}
+
+// UpdateClaudeCodeOnly sets the "claude_code_only" field to the value that was provided on create.
+func (u *GroupUpsert) UpdateClaudeCodeOnly() *GroupUpsert {
+	u.SetExcluded(group.FieldClaudeCodeOnly)
+	return u
+}
+
+// SetFallbackGroupID sets the "fallback_group_id" field.
+func (u *GroupUpsert) SetFallbackGroupID(v int64) *GroupUpsert {
+	u.Set(group.FieldFallbackGroupID, v)
+	return u
+}
+
+// UpdateFallbackGroupID sets the "fallback_group_id" field to the value that was provided on create.
+func (u *GroupUpsert) UpdateFallbackGroupID() *GroupUpsert {
+	u.SetExcluded(group.FieldFallbackGroupID)
+	return u
+}
+
+// AddFallbackGroupID adds v to the "fallback_group_id" field.
+func (u *GroupUpsert) AddFallbackGroupID(v int64) *GroupUpsert {
+	u.Add(group.FieldFallbackGroupID, v)
+	return u
+}
+
+// ClearFallbackGroupID clears the value of the "fallback_group_id" field.
+func (u *GroupUpsert) ClearFallbackGroupID() *GroupUpsert {
+	u.SetNull(group.FieldFallbackGroupID)
+	return u
+}
+
 // UpdateNewValues updates the mutable fields using the new values that were set on create.
 // Using this option is equivalent to using:
 //
@@ -1395,6 +1474,48 @@ func (u *GroupUpsertOne) ClearImagePrice4k() *GroupUpsertOne {
 	})
 }
 
+// SetClaudeCodeOnly sets the "claude_code_only" field.
+func (u *GroupUpsertOne) SetClaudeCodeOnly(v bool) *GroupUpsertOne {
+	return u.Update(func(s *GroupUpsert) {
+		s.SetClaudeCodeOnly(v)
+	})
+}
+
+// UpdateClaudeCodeOnly sets the "claude_code_only" field to the value that was provided on create.
+func (u *GroupUpsertOne) UpdateClaudeCodeOnly() *GroupUpsertOne {
+	return u.Update(func(s *GroupUpsert) {
+		s.UpdateClaudeCodeOnly()
+	})
+}
+
+// SetFallbackGroupID sets the "fallback_group_id" field.
+func (u *GroupUpsertOne) SetFallbackGroupID(v int64) *GroupUpsertOne {
+	return u.Update(func(s *GroupUpsert) {
+		s.SetFallbackGroupID(v)
+	})
+}
+
+// AddFallbackGroupID adds v to the "fallback_group_id" field.
+func (u *GroupUpsertOne) AddFallbackGroupID(v int64) *GroupUpsertOne {
+	return u.Update(func(s *GroupUpsert) {
+		s.AddFallbackGroupID(v)
+	})
+}
+
+// UpdateFallbackGroupID sets the "fallback_group_id" field to the value that was provided on create.
+func (u *GroupUpsertOne) UpdateFallbackGroupID() *GroupUpsertOne {
+	return u.Update(func(s *GroupUpsert) {
+		s.UpdateFallbackGroupID()
+	})
+}
+
+// ClearFallbackGroupID clears the value of the "fallback_group_id" field.
+func (u *GroupUpsertOne) ClearFallbackGroupID() *GroupUpsertOne {
+	return u.Update(func(s *GroupUpsert) {
+		s.ClearFallbackGroupID()
+	})
+}
+
 // Exec executes the query.
 func (u *GroupUpsertOne) Exec(ctx context.Context) error {
 	if len(u.create.conflict) == 0 {
@@ -1942,6 +2063,48 @@ func (u *GroupUpsertBulk) ClearImagePrice4k() *GroupUpsertBulk {
 	})
 }
 
+// SetClaudeCodeOnly sets the "claude_code_only" field.
+func (u *GroupUpsertBulk) SetClaudeCodeOnly(v bool) *GroupUpsertBulk {
+	return u.Update(func(s *GroupUpsert) {
+		s.SetClaudeCodeOnly(v)
+	})
+}
+
+// UpdateClaudeCodeOnly sets the "claude_code_only" field to the value that was provided on create.
+func (u *GroupUpsertBulk) UpdateClaudeCodeOnly() *GroupUpsertBulk {
+	return u.Update(func(s *GroupUpsert) {
+		s.UpdateClaudeCodeOnly()
+	})
+}
+
+// SetFallbackGroupID sets the "fallback_group_id" field.
+func (u *GroupUpsertBulk) SetFallbackGroupID(v int64) *GroupUpsertBulk {
+	return u.Update(func(s *GroupUpsert) {
+		s.SetFallbackGroupID(v)
+	})
+}
+
+// AddFallbackGroupID adds v to the "fallback_group_id" field.
+func (u *GroupUpsertBulk) AddFallbackGroupID(v int64) *GroupUpsertBulk {
+	return u.Update(func(s *GroupUpsert) {
+		s.AddFallbackGroupID(v)
+	})
+}
+
+// UpdateFallbackGroupID sets the "fallback_group_id" field to the value that was provided on create.
+func (u *GroupUpsertBulk) UpdateFallbackGroupID() *GroupUpsertBulk {
+	return u.Update(func(s *GroupUpsert) {
+		s.UpdateFallbackGroupID()
+	})
+}
+
+// ClearFallbackGroupID clears the value of the "fallback_group_id" field.
+func (u *GroupUpsertBulk) ClearFallbackGroupID() *GroupUpsertBulk {
+	return u.Update(func(s *GroupUpsert) {
+		s.ClearFallbackGroupID()
+	})
+}
+
 // Exec executes the query.
 func (u *GroupUpsertBulk) Exec(ctx context.Context) error {
 	if u.create.err != nil {

backend/ent/group_update.go

@@ -354,6 +354,47 @@ func (_u *GroupUpdate) ClearImagePrice4k() *GroupUpdate {
 	return _u
 }
 
+// SetClaudeCodeOnly sets the "claude_code_only" field.
+func (_u *GroupUpdate) SetClaudeCodeOnly(v bool) *GroupUpdate {
+	_u.mutation.SetClaudeCodeOnly(v)
+	return _u
+}
+
+// SetNillableClaudeCodeOnly sets the "claude_code_only" field if the given value is not nil.
+func (_u *GroupUpdate) SetNillableClaudeCodeOnly(v *bool) *GroupUpdate {
+	if v != nil {
+		_u.SetClaudeCodeOnly(*v)
+	}
+	return _u
+}
+
+// SetFallbackGroupID sets the "fallback_group_id" field.
+func (_u *GroupUpdate) SetFallbackGroupID(v int64) *GroupUpdate {
+	_u.mutation.ResetFallbackGroupID()
+	_u.mutation.SetFallbackGroupID(v)
+	return _u
+}
+
+// SetNillableFallbackGroupID sets the "fallback_group_id" field if the given value is not nil.
+func (_u *GroupUpdate) SetNillableFallbackGroupID(v *int64) *GroupUpdate {
+	if v != nil {
+		_u.SetFallbackGroupID(*v)
+	}
+	return _u
+}
+
+// AddFallbackGroupID adds value to the "fallback_group_id" field.
+func (_u *GroupUpdate) AddFallbackGroupID(v int64) *GroupUpdate {
+	_u.mutation.AddFallbackGroupID(v)
+	return _u
+}
+
+// ClearFallbackGroupID clears the value of the "fallback_group_id" field.
+func (_u *GroupUpdate) ClearFallbackGroupID() *GroupUpdate {
+	_u.mutation.ClearFallbackGroupID()
+	return _u
+}
+
 // AddAPIKeyIDs adds the "api_keys" edge to the APIKey entity by IDs.
 func (_u *GroupUpdate) AddAPIKeyIDs(ids ...int64) *GroupUpdate {
 	_u.mutation.AddAPIKeyIDs(ids...)
@@ -750,6 +791,18 @@ func (_u *GroupUpdate) sqlSave(ctx context.Context) (_node int, err error) {
 	if _u.mutation.ImagePrice4kCleared() {
 		_spec.ClearField(group.FieldImagePrice4k, field.TypeFloat64)
 	}
+	if value, ok := _u.mutation.ClaudeCodeOnly(); ok {
+		_spec.SetField(group.FieldClaudeCodeOnly, field.TypeBool, value)
+	}
+	if value, ok := _u.mutation.FallbackGroupID(); ok {
+		_spec.SetField(group.FieldFallbackGroupID, field.TypeInt64, value)
+	}
+	if value, ok := _u.mutation.AddedFallbackGroupID(); ok {
+		_spec.AddField(group.FieldFallbackGroupID, field.TypeInt64, value)
+	}
+	if _u.mutation.FallbackGroupIDCleared() {
+		_spec.ClearField(group.FieldFallbackGroupID, field.TypeInt64)
+	}
 	if _u.mutation.APIKeysCleared() {
 		edge := &sqlgraph.EdgeSpec{
 			Rel:     sqlgraph.O2M,
@@ -1384,6 +1437,47 @@ func (_u *GroupUpdateOne) ClearImagePrice4k() *GroupUpdateOne {
 	return _u
 }
 
+// SetClaudeCodeOnly sets the "claude_code_only" field.
+func (_u *GroupUpdateOne) SetClaudeCodeOnly(v bool) *GroupUpdateOne {
+	_u.mutation.SetClaudeCodeOnly(v)
+	return _u
+}
+
+// SetNillableClaudeCodeOnly sets the "claude_code_only" field if the given value is not nil.
+func (_u *GroupUpdateOne) SetNillableClaudeCodeOnly(v *bool) *GroupUpdateOne {
+	if v != nil {
+		_u.SetClaudeCodeOnly(*v)
+	}
+	return _u
+}
+
+// SetFallbackGroupID sets the "fallback_group_id" field.
+func (_u *GroupUpdateOne) SetFallbackGroupID(v int64) *GroupUpdateOne {
+	_u.mutation.ResetFallbackGroupID()
+	_u.mutation.SetFallbackGroupID(v)
+	return _u
+}
+
+// SetNillableFallbackGroupID sets the "fallback_group_id" field if the given value is not nil.
+func (_u *GroupUpdateOne) SetNillableFallbackGroupID(v *int64) *GroupUpdateOne {
+	if v != nil {
+		_u.SetFallbackGroupID(*v)
+	}
+	return _u
+}
+
+// AddFallbackGroupID adds value to the "fallback_group_id" field.
+func (_u *GroupUpdateOne) AddFallbackGroupID(v int64) *GroupUpdateOne {
+	_u.mutation.AddFallbackGroupID(v)
+	return _u
+}
+
+// ClearFallbackGroupID clears the value of the "fallback_group_id" field.
+func (_u *GroupUpdateOne) ClearFallbackGroupID() *GroupUpdateOne {
+	_u.mutation.ClearFallbackGroupID()
+	return _u
+}
+
 // AddAPIKeyIDs adds the "api_keys" edge to the APIKey entity by IDs.
 func (_u *GroupUpdateOne) AddAPIKeyIDs(ids ...int64) *GroupUpdateOne {
 	_u.mutation.AddAPIKeyIDs(ids...)
@@ -1810,6 +1904,18 @@ func (_u *GroupUpdateOne) sqlSave(ctx context.Context) (_node *Group, err error)
 	if _u.mutation.ImagePrice4kCleared() {
 		_spec.ClearField(group.FieldImagePrice4k, field.TypeFloat64)
 	}
+	if value, ok := _u.mutation.ClaudeCodeOnly(); ok {
+		_spec.SetField(group.FieldClaudeCodeOnly, field.TypeBool, value)
+	}
+	if value, ok := _u.mutation.FallbackGroupID(); ok {
+		_spec.SetField(group.FieldFallbackGroupID, field.TypeInt64, value)
+	}
+	if value, ok := _u.mutation.AddedFallbackGroupID(); ok {
+		_spec.AddField(group.FieldFallbackGroupID, field.TypeInt64, value)
+	}
+	if _u.mutation.FallbackGroupIDCleared() {
+		_spec.ClearField(group.FieldFallbackGroupID, field.TypeInt64)
+	}
 	if _u.mutation.APIKeysCleared() {
 		edge := &sqlgraph.EdgeSpec{
 			Rel:     sqlgraph.O2M,

backend/ent/migrate/schema.go

@@ -221,6 +221,8 @@ var (
 		{Name: "image_price_1k", Type: field.TypeFloat64, Nullable: true, SchemaType: map[string]string{"postgres": "decimal(20,8)"}},
 		{Name: "image_price_2k", Type: field.TypeFloat64, Nullable: true, SchemaType: map[string]string{"postgres": "decimal(20,8)"}},
 		{Name: "image_price_4k", Type: field.TypeFloat64, Nullable: true, SchemaType: map[string]string{"postgres": "decimal(20,8)"}},
+		{Name: "claude_code_only", Type: field.TypeBool, Default: false},
+		{Name: "fallback_group_id", Type: field.TypeInt64, Nullable: true},
 	}
 	// GroupsTable holds the schema information for the "groups" table.
 	GroupsTable = &schema.Table{

backend/ent/mutation.go

@@ -3590,6 +3590,9 @@ type GroupMutation struct {
 	addimage_price_2k        *float64
 	image_price_4k           *float64
 	addimage_price_4k        *float64
+	claude_code_only         *bool
+	fallback_group_id        *int64
+	addfallback_group_id     *int64
 	clearedFields            map[string]struct{}
 	api_keys                 map[int64]struct{}
 	removedapi_keys          map[int64]struct{}
@@ -4594,6 +4597,112 @@ func (m *GroupMutation) ResetImagePrice4k() {
 	delete(m.clearedFields, group.FieldImagePrice4k)
 }
 
+// SetClaudeCodeOnly sets the "claude_code_only" field.
+func (m *GroupMutation) SetClaudeCodeOnly(b bool) {
+	m.claude_code_only = &b
+}
+
+// ClaudeCodeOnly returns the value of the "claude_code_only" field in the mutation.
+func (m *GroupMutation) ClaudeCodeOnly() (r bool, exists bool) {
+	v := m.claude_code_only
+	if v == nil {
+		return
+	}
+	return *v, true
+}
+
+// OldClaudeCodeOnly returns the old "claude_code_only" field's value of the Group entity.
+// If the Group object wasn't provided to the builder, the object is fetched from the database.
+// An error is returned if the mutation operation is not UpdateOne, or the database query fails.
+func (m *GroupMutation) OldClaudeCodeOnly(ctx context.Context) (v bool, err error) {
+	if !m.op.Is(OpUpdateOne) {
+		return v, errors.New("OldClaudeCodeOnly is only allowed on UpdateOne operations")
+	}
+	if m.id == nil || m.oldValue == nil {
+		return v, errors.New("OldClaudeCodeOnly requires an ID field in the mutation")
+	}
+	oldValue, err := m.oldValue(ctx)
+	if err != nil {
+		return v, fmt.Errorf("querying old value for OldClaudeCodeOnly: %w", err)
+	}
+	return oldValue.ClaudeCodeOnly, nil
+}
+
+// ResetClaudeCodeOnly resets all changes to the "claude_code_only" field.
+func (m *GroupMutation) ResetClaudeCodeOnly() {
+	m.claude_code_only = nil
+}
+
+// SetFallbackGroupID sets the "fallback_group_id" field.
+func (m *GroupMutation) SetFallbackGroupID(i int64) {
+	m.fallback_group_id = &i
+	m.addfallback_group_id = nil
+}
+
+// FallbackGroupID returns the value of the "fallback_group_id" field in the mutation.
+func (m *GroupMutation) FallbackGroupID() (r int64, exists bool) {
+	v := m.fallback_group_id
+	if v == nil {
+		return
+	}
+	return *v, true
+}
+
+// OldFallbackGroupID returns the old "fallback_group_id" field's value of the Group entity.
+// If the Group object wasn't provided to the builder, the object is fetched from the database.
+// An error is returned if the mutation operation is not UpdateOne, or the database query fails.
+func (m *GroupMutation) OldFallbackGroupID(ctx context.Context) (v *int64, err error) {
+	if !m.op.Is(OpUpdateOne) {
+		return v, errors.New("OldFallbackGroupID is only allowed on UpdateOne operations")
+	}
+	if m.id == nil || m.oldValue == nil {
+		return v, errors.New("OldFallbackGroupID requires an ID field in the mutation")
+	}
+	oldValue, err := m.oldValue(ctx)
+	if err != nil {
+		return v, fmt.Errorf("querying old value for OldFallbackGroupID: %w", err)
+	}
+	return oldValue.FallbackGroupID, nil
+}
+
+// AddFallbackGroupID adds i to the "fallback_group_id" field.
+func (m *GroupMutation) AddFallbackGroupID(i int64) {
+	if m.addfallback_group_id != nil {
+		*m.addfallback_group_id += i
+	} else {
+		m.addfallback_group_id = &i
+	}
+}
+
+// AddedFallbackGroupID returns the value that was added to the "fallback_group_id" field in this mutation.
+func (m *GroupMutation) AddedFallbackGroupID() (r int64, exists bool) {
+	v := m.addfallback_group_id
+	if v == nil {
+		return
+	}
+	return *v, true
+}
+
+// ClearFallbackGroupID clears the value of the "fallback_group_id" field.
+func (m *GroupMutation) ClearFallbackGroupID() {
+	m.fallback_group_id = nil
+	m.addfallback_group_id = nil
+	m.clearedFields[group.FieldFallbackGroupID] = struct{}{}
+}
+
+// FallbackGroupIDCleared returns if the "fallback_group_id" field was cleared in this mutation.
+func (m *GroupMutation) FallbackGroupIDCleared() bool {
+	_, ok := m.clearedFields[group.FieldFallbackGroupID]
+	return ok
+}
+
+// ResetFallbackGroupID resets all changes to the "fallback_group_id" field.
+func (m *GroupMutation) ResetFallbackGroupID() {
+	m.fallback_group_id = nil
+	m.addfallback_group_id = nil
+	delete(m.clearedFields, group.FieldFallbackGroupID)
+}
+
 // AddAPIKeyIDs adds the "api_keys" edge to the APIKey entity by ids.
 func (m *GroupMutation) AddAPIKeyIDs(ids ...int64) {
 	if m.api_keys == nil {
@@ -4952,7 +5061,7 @@ func (m *GroupMutation) Type() string {
 // order to get all numeric fields that were incremented/decremented, call
 // AddedFields().
 func (m *GroupMutation) Fields() []string {
-	fields := make([]string, 0, 17)
+	fields := make([]string, 0, 19)
 	if m.created_at != nil {
 		fields = append(fields, group.FieldCreatedAt)
 	}
@@ -5004,6 +5113,12 @@ func (m *GroupMutation) Fields() []string {
 	if m.image_price_4k != nil {
 		fields = append(fields, group.FieldImagePrice4k)
 	}
+	if m.claude_code_only != nil {
+		fields = append(fields, group.FieldClaudeCodeOnly)
+	}
+	if m.fallback_group_id != nil {
+		fields = append(fields, group.FieldFallbackGroupID)
+	}
 	return fields
 }
 
@@ -5046,6 +5161,10 @@ func (m *GroupMutation) Field(name string) (ent.Value, bool) {
 		return m.ImagePrice2k()
 	case group.FieldImagePrice4k:
 		return m.ImagePrice4k()
+	case group.FieldClaudeCodeOnly:
+		return m.ClaudeCodeOnly()
+	case group.FieldFallbackGroupID:
+		return m.FallbackGroupID()
 	}
 	return nil, false
 }
@@ -5089,6 +5208,10 @@ func (m *GroupMutation) OldField(ctx context.Context, name string) (ent.Value, e
 		return m.OldImagePrice2k(ctx)
 	case group.FieldImagePrice4k:
 		return m.OldImagePrice4k(ctx)
+	case group.FieldClaudeCodeOnly:
+		return m.OldClaudeCodeOnly(ctx)
+	case group.FieldFallbackGroupID:
+		return m.OldFallbackGroupID(ctx)
 	}
 	return nil, fmt.Errorf("unknown Group field %s", name)
 }
@@ -5217,6 +5340,20 @@ func (m *GroupMutation) SetField(name string, value ent.Value) error {
 		}
 		m.SetImagePrice4k(v)
 		return nil
+	case group.FieldClaudeCodeOnly:
+		v, ok := value.(bool)
+		if !ok {
+			return fmt.Errorf("unexpected type %T for field %s", value, name)
+		}
+		m.SetClaudeCodeOnly(v)
+		return nil
+	case group.FieldFallbackGroupID:
+		v, ok := value.(int64)
+		if !ok {
+			return fmt.Errorf("unexpected type %T for field %s", value, name)
+		}
+		m.SetFallbackGroupID(v)
+		return nil
 	}
 	return fmt.Errorf("unknown Group field %s", name)
 }
@@ -5249,6 +5386,9 @@ func (m *GroupMutation) AddedFields() []string {
 	if m.addimage_price_4k != nil {
 		fields = append(fields, group.FieldImagePrice4k)
 	}
+	if m.addfallback_group_id != nil {
+		fields = append(fields, group.FieldFallbackGroupID)
+	}
 	return fields
 }
 
@@ -5273,6 +5413,8 @@ func (m *GroupMutation) AddedField(name string) (ent.Value, bool) {
 		return m.AddedImagePrice2k()
 	case group.FieldImagePrice4k:
 		return m.AddedImagePrice4k()
+	case group.FieldFallbackGroupID:
+		return m.AddedFallbackGroupID()
 	}
 	return nil, false
 }
@@ -5338,6 +5480,13 @@ func (m *GroupMutation) AddField(name string, value ent.Value) error {
 		}
 		m.AddImagePrice4k(v)
 		return nil
+	case group.FieldFallbackGroupID:
+		v, ok := value.(int64)
+		if !ok {
+			return fmt.Errorf("unexpected type %T for field %s", value, name)
+		}
+		m.AddFallbackGroupID(v)
+		return nil
 	}
 	return fmt.Errorf("unknown Group numeric field %s", name)
 }
@@ -5370,6 +5519,9 @@ func (m *GroupMutation) ClearedFields() []string {
 	if m.FieldCleared(group.FieldImagePrice4k) {
 		fields = append(fields, group.FieldImagePrice4k)
 	}
+	if m.FieldCleared(group.FieldFallbackGroupID) {
+		fields = append(fields, group.FieldFallbackGroupID)
+	}
 	return fields
 }
 
@@ -5408,6 +5560,9 @@ func (m *GroupMutation) ClearField(name string) error {
 	case group.FieldImagePrice4k:
 		m.ClearImagePrice4k()
 		return nil
+	case group.FieldFallbackGroupID:
+		m.ClearFallbackGroupID()
+		return nil
 	}
 	return fmt.Errorf("unknown Group nullable field %s", name)
 }
@@ -5467,6 +5622,12 @@ func (m *GroupMutation) ResetField(name string) error {
 	case group.FieldImagePrice4k:
 		m.ResetImagePrice4k()
 		return nil
+	case group.FieldClaudeCodeOnly:
+		m.ResetClaudeCodeOnly()
+		return nil
+	case group.FieldFallbackGroupID:
+		m.ResetFallbackGroupID()
+		return nil
 	}
 	return fmt.Errorf("unknown Group field %s", name)
 }

backend/ent/runtime/runtime.go

@@ -270,6 +270,10 @@ func init() {
 	groupDescDefaultValidityDays := groupFields[10].Descriptor()
 	// group.DefaultDefaultValidityDays holds the default value on creation for the default_validity_days field.
 	group.DefaultDefaultValidityDays = groupDescDefaultValidityDays.Default.(int)
+	// groupDescClaudeCodeOnly is the schema descriptor for claude_code_only field.
+	groupDescClaudeCodeOnly := groupFields[14].Descriptor()
+	// group.DefaultClaudeCodeOnly holds the default value on creation for the claude_code_only field.
+	group.DefaultClaudeCodeOnly = groupDescClaudeCodeOnly.Default.(bool)
 	proxyMixin := schema.Proxy{}.Mixin()
 	proxyMixinHooks1 := proxyMixin[1].Hooks()
 	proxy.Hooks[0] = proxyMixinHooks1[0]

backend/ent/schema/group.go

@@ -86,6 +86,15 @@ func (Group) Fields() []ent.Field {
 			Optional().
 			Nillable().
 			SchemaType(map[string]string{dialect.Postgres: "decimal(20,8)"}),
+
+		// Claude Code 客户端限制 (added by migration 029)
+		field.Bool("claude_code_only").
+			Default(false).
+			Comment("是否仅允许 Claude Code 客户端"),
+		field.Int64("fallback_group_id").
+			Optional().
+			Nillable().
+			Comment("非 Claude Code 请求降级使用的分组 ID"),
 	}
 }
 
@@ -101,6 +110,8 @@ func (Group) Edges() []ent.Edge {
 		edge.From("allowed_users", User.Type).
 			Ref("allowed_groups").
 			Through("user_allowed_groups", UserAllowedGroup.Type),
+		// 注意：fallback_group_id 直接作为字段使用，不定义 edge
+		// 这样允许多个分组指向同一个降级分组（M2O 关系）
 	}
 }