fix(channel-monitor): drop soft delete, refactor feature flag to declarative form

### 后端修复：日志表不该用软删除

channel_monitor_histories / channel_monitor_daily_rollups 都是日志/聚合表，
没有恢复需求。110 里加的 SoftDeleteMixin 会让 DELETE 自动变成 UPDATE deleted_at，
导致行和索引只增不减，徒增磁盘占用和查询成本。

改回分批物理删（参考 OpsCleanupService.deleteOldRowsByID 模板）：

- ent schema 移除 SoftDeleteMixin，重新 go generate
- repo 新增 deleteChannelMonitorBatched 辅助 + 两条 prune SQL 常量
  （WITH batch AS SELECT id LIMIT 5000 → DELETE IN batch）
- DeleteHistoryBefore / DeleteRollupsBefore 改调分批 raw SQL
- 移除 ComputeAvailability / ComputeAvailabilityForMonitors / UpsertDailyRollupsFor /
  ListLatestPerModel / ListLatestForMonitorIDs / ListRecentHistoryForMonitors 等
  raw SQL 中的 deleted_at IS NULL 过滤
- UpsertDailyRollupsFor 的 ON CONFLICT 去掉 deleted_at = NULL 重置
- migration 111 DROP COLUMN deleted_at + 对应索引（110 已部署但 maintenance
  首跑在次日 02:00，此时尚无业务数据在依赖软删除）

### 前端重构：feature flag 声明式 + 复用

AppSidebar.vue 里 7 处 `...(flag ? [item] : [])` 样板代码删光，改为 NavItem 加
featureFlag?: () => boolean | undefined 字段，加一个 applyFeatureFlags 递归
过滤（含 children）。语义统一为 `!== false`（宽容策略，undefined 时默认显示，
避免 public settings 未加载完成时菜单闪烁消失 — 对应用户反馈"刷新后菜单消失
要去保存设置才回来"）。

- 集中声明 4 个 flag getter：flagChannelMonitor / flagPayment /
  flagOpsMonitoring / flagAdminPayment
- 提取 buildSelfNavItems 复用用户端主菜单和管理员"我的账户"子菜单
- 未来新增开关：在统一位置加一个 flag getter + 给对应 NavItem 加字段
  （不用再动渲染逻辑）

bump 0.1.114.29

backend/ent/channelmonitorhistory_create.go

@@ -23,20 +23,6 @@ type ChannelMonitorHistoryCreate struct {
 	conflict []sql.ConflictOption
 }
 
-// SetDeletedAt sets the "deleted_at" field.
-func (_c *ChannelMonitorHistoryCreate) SetDeletedAt(v time.Time) *ChannelMonitorHistoryCreate {
-	_c.mutation.SetDeletedAt(v)
-	return _c
-}
-
-// SetNillableDeletedAt sets the "deleted_at" field if the given value is not nil.
-func (_c *ChannelMonitorHistoryCreate) SetNillableDeletedAt(v *time.Time) *ChannelMonitorHistoryCreate {
-	if v != nil {
-		_c.SetDeletedAt(*v)
-	}
-	return _c
-}
-
 // SetMonitorID sets the "monitor_id" field.
 func (_c *ChannelMonitorHistoryCreate) SetMonitorID(v int64) *ChannelMonitorHistoryCreate {
 	_c.mutation.SetMonitorID(v)
@@ -123,9 +109,7 @@ func (_c *ChannelMonitorHistoryCreate) Mutation() *ChannelMonitorHistoryMutation
 
 // Save creates the ChannelMonitorHistory in the database.
 func (_c *ChannelMonitorHistoryCreate) Save(ctx context.Context) (*ChannelMonitorHistory, error) {
-	if err := _c.defaults(); err != nil {
-		return nil, err
-	}
+	_c.defaults()
 	return withHooks(ctx, _c.sqlSave, _c.mutation, _c.hooks)
 }
 
@@ -152,19 +136,15 @@ func (_c *ChannelMonitorHistoryCreate) ExecX(ctx context.Context) {
 }
 
 // defaults sets the default values of the builder before save.
-func (_c *ChannelMonitorHistoryCreate) defaults() error {
+func (_c *ChannelMonitorHistoryCreate) defaults() {
 	if _, ok := _c.mutation.Message(); !ok {
 		v := channelmonitorhistory.DefaultMessage
 		_c.mutation.SetMessage(v)
 	}
 	if _, ok := _c.mutation.CheckedAt(); !ok {
-		if channelmonitorhistory.DefaultCheckedAt == nil {
-			return fmt.Errorf("ent: uninitialized channelmonitorhistory.DefaultCheckedAt (forgotten import ent/runtime?)")
-		}
 		v := channelmonitorhistory.DefaultCheckedAt()
 		_c.mutation.SetCheckedAt(v)
 	}
-	return nil
 }
 
 // check runs all checks and user-defined validators on the builder.
@@ -226,10 +206,6 @@ func (_c *ChannelMonitorHistoryCreate) createSpec() (*ChannelMonitorHistory, *sq
 		_spec = sqlgraph.NewCreateSpec(channelmonitorhistory.Table, sqlgraph.NewFieldSpec(channelmonitorhistory.FieldID, field.TypeInt64))
 	)
 	_spec.OnConflict = _c.conflict
-	if value, ok := _c.mutation.DeletedAt(); ok {
-		_spec.SetField(channelmonitorhistory.FieldDeletedAt, field.TypeTime, value)
-		_node.DeletedAt = &value
-	}
 	if value, ok := _c.mutation.Model(); ok {
 		_spec.SetField(channelmonitorhistory.FieldModel, field.TypeString, value)
 		_node.Model = value
@@ -278,7 +254,7 @@ func (_c *ChannelMonitorHistoryCreate) createSpec() (*ChannelMonitorHistory, *sq
 // of the `INSERT` statement. For example:
 //
 //	client.ChannelMonitorHistory.Create().
-//		SetDeletedAt(v).
+//		SetMonitorID(v).
 //		OnConflict(
 //			// Update the row with the new values
 //			// the was proposed for insertion.
@@ -287,7 +263,7 @@ func (_c *ChannelMonitorHistoryCreate) createSpec() (*ChannelMonitorHistory, *sq
 //		// Override some of the fields with custom
 //		// update values.
 //		Update(func(u *ent.ChannelMonitorHistoryUpsert) {
-//			SetDeletedAt(v+v).
+//			SetMonitorID(v+v).
 //		}).
 //		Exec(ctx)
 func (_c *ChannelMonitorHistoryCreate) OnConflict(opts ...sql.ConflictOption) *ChannelMonitorHistoryUpsertOne {
@@ -323,24 +299,6 @@ type (
 	}
 )
 
-// SetDeletedAt sets the "deleted_at" field.
-func (u *ChannelMonitorHistoryUpsert) SetDeletedAt(v time.Time) *ChannelMonitorHistoryUpsert {
-	u.Set(channelmonitorhistory.FieldDeletedAt, v)
-	return u
-}
-
-// UpdateDeletedAt sets the "deleted_at" field to the value that was provided on create.
-func (u *ChannelMonitorHistoryUpsert) UpdateDeletedAt() *ChannelMonitorHistoryUpsert {
-	u.SetExcluded(channelmonitorhistory.FieldDeletedAt)
-	return u
-}
-
-// ClearDeletedAt clears the value of the "deleted_at" field.
-func (u *ChannelMonitorHistoryUpsert) ClearDeletedAt() *ChannelMonitorHistoryUpsert {
-	u.SetNull(channelmonitorhistory.FieldDeletedAt)
-	return u
-}
-
 // SetMonitorID sets the "monitor_id" field.
 func (u *ChannelMonitorHistoryUpsert) SetMonitorID(v int64) *ChannelMonitorHistoryUpsert {
 	u.Set(channelmonitorhistory.FieldMonitorID, v)
@@ -495,27 +453,6 @@ func (u *ChannelMonitorHistoryUpsertOne) Update(set func(*ChannelMonitorHistoryU
 	return u
 }
 
-// SetDeletedAt sets the "deleted_at" field.
-func (u *ChannelMonitorHistoryUpsertOne) SetDeletedAt(v time.Time) *ChannelMonitorHistoryUpsertOne {
-	return u.Update(func(s *ChannelMonitorHistoryUpsert) {
-		s.SetDeletedAt(v)
-	})
-}
-
-// UpdateDeletedAt sets the "deleted_at" field to the value that was provided on create.
-func (u *ChannelMonitorHistoryUpsertOne) UpdateDeletedAt() *ChannelMonitorHistoryUpsertOne {
-	return u.Update(func(s *ChannelMonitorHistoryUpsert) {
-		s.UpdateDeletedAt()
-	})
-}
-
-// ClearDeletedAt clears the value of the "deleted_at" field.
-func (u *ChannelMonitorHistoryUpsertOne) ClearDeletedAt() *ChannelMonitorHistoryUpsertOne {
-	return u.Update(func(s *ChannelMonitorHistoryUpsert) {
-		s.ClearDeletedAt()
-	})
-}
-
 // SetMonitorID sets the "monitor_id" field.
 func (u *ChannelMonitorHistoryUpsertOne) SetMonitorID(v int64) *ChannelMonitorHistoryUpsertOne {
 	return u.Update(func(s *ChannelMonitorHistoryUpsert) {
@@ -784,7 +721,7 @@ func (_c *ChannelMonitorHistoryCreateBulk) ExecX(ctx context.Context) {
 //		// Override some of the fields with custom
 //		// update values.
 //		Update(func(u *ent.ChannelMonitorHistoryUpsert) {
-//			SetDeletedAt(v+v).
+//			SetMonitorID(v+v).
 //		}).
 //		Exec(ctx)
 func (_c *ChannelMonitorHistoryCreateBulk) OnConflict(opts ...sql.ConflictOption) *ChannelMonitorHistoryUpsertBulk {
@@ -853,27 +790,6 @@ func (u *ChannelMonitorHistoryUpsertBulk) Update(set func(*ChannelMonitorHistory
 	return u
 }
 
-// SetDeletedAt sets the "deleted_at" field.
-func (u *ChannelMonitorHistoryUpsertBulk) SetDeletedAt(v time.Time) *ChannelMonitorHistoryUpsertBulk {
-	return u.Update(func(s *ChannelMonitorHistoryUpsert) {
-		s.SetDeletedAt(v)
-	})
-}
-
-// UpdateDeletedAt sets the "deleted_at" field to the value that was provided on create.
-func (u *ChannelMonitorHistoryUpsertBulk) UpdateDeletedAt() *ChannelMonitorHistoryUpsertBulk {
-	return u.Update(func(s *ChannelMonitorHistoryUpsert) {
-		s.UpdateDeletedAt()
-	})
-}
-
-// ClearDeletedAt clears the value of the "deleted_at" field.
-func (u *ChannelMonitorHistoryUpsertBulk) ClearDeletedAt() *ChannelMonitorHistoryUpsertBulk {
-	return u.Update(func(s *ChannelMonitorHistoryUpsert) {
-		s.ClearDeletedAt()
-	})
-}
-
 // SetMonitorID sets the "monitor_id" field.
 func (u *ChannelMonitorHistoryUpsertBulk) SetMonitorID(v int64) *ChannelMonitorHistoryUpsertBulk {
 	return u.Update(func(s *ChannelMonitorHistoryUpsert) {