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/channelmonitordailyrollup_update.go

@@ -29,26 +29,6 @@ func (_u *ChannelMonitorDailyRollupUpdate) Where(ps ...predicate.ChannelMonitorD
 	return _u
 }
 
-// SetDeletedAt sets the "deleted_at" field.
-func (_u *ChannelMonitorDailyRollupUpdate) SetDeletedAt(v time.Time) *ChannelMonitorDailyRollupUpdate {
-	_u.mutation.SetDeletedAt(v)
-	return _u
-}
-
-// SetNillableDeletedAt sets the "deleted_at" field if the given value is not nil.
-func (_u *ChannelMonitorDailyRollupUpdate) SetNillableDeletedAt(v *time.Time) *ChannelMonitorDailyRollupUpdate {
-	if v != nil {
-		_u.SetDeletedAt(*v)
-	}
-	return _u
-}
-
-// ClearDeletedAt clears the value of the "deleted_at" field.
-func (_u *ChannelMonitorDailyRollupUpdate) ClearDeletedAt() *ChannelMonitorDailyRollupUpdate {
-	_u.mutation.ClearDeletedAt()
-	return _u
-}
-
 // SetMonitorID sets the "monitor_id" field.
 func (_u *ChannelMonitorDailyRollupUpdate) SetMonitorID(v int64) *ChannelMonitorDailyRollupUpdate {
 	_u.mutation.SetMonitorID(v)
@@ -325,9 +305,7 @@ func (_u *ChannelMonitorDailyRollupUpdate) ClearMonitor() *ChannelMonitorDailyRo
 
 // Save executes the query and returns the number of nodes affected by the update operation.
 func (_u *ChannelMonitorDailyRollupUpdate) Save(ctx context.Context) (int, error) {
-	if err := _u.defaults(); err != nil {
-		return 0, err
-	}
+	_u.defaults()
 	return withHooks(ctx, _u.sqlSave, _u.mutation, _u.hooks)
 }
 
@@ -354,15 +332,11 @@ func (_u *ChannelMonitorDailyRollupUpdate) ExecX(ctx context.Context) {
 }
 
 // defaults sets the default values of the builder before save.
-func (_u *ChannelMonitorDailyRollupUpdate) defaults() error {
+func (_u *ChannelMonitorDailyRollupUpdate) defaults() {
 	if _, ok := _u.mutation.ComputedAt(); !ok {
-		if channelmonitordailyrollup.UpdateDefaultComputedAt == nil {
-			return fmt.Errorf("ent: uninitialized channelmonitordailyrollup.UpdateDefaultComputedAt (forgotten import ent/runtime?)")
-		}
 		v := channelmonitordailyrollup.UpdateDefaultComputedAt()
 		_u.mutation.SetComputedAt(v)
 	}
-	return nil
 }
 
 // check runs all checks and user-defined validators on the builder.
@@ -390,12 +364,6 @@ func (_u *ChannelMonitorDailyRollupUpdate) sqlSave(ctx context.Context) (_node i
 			}
 		}
 	}
-	if value, ok := _u.mutation.DeletedAt(); ok {
-		_spec.SetField(channelmonitordailyrollup.FieldDeletedAt, field.TypeTime, value)
-	}
-	if _u.mutation.DeletedAtCleared() {
-		_spec.ClearField(channelmonitordailyrollup.FieldDeletedAt, field.TypeTime)
-	}
 	if value, ok := _u.mutation.Model(); ok {
 		_spec.SetField(channelmonitordailyrollup.FieldModel, field.TypeString, value)
 	}
@@ -514,26 +482,6 @@ type ChannelMonitorDailyRollupUpdateOne struct {
 	mutation *ChannelMonitorDailyRollupMutation
 }
 
-// SetDeletedAt sets the "deleted_at" field.
-func (_u *ChannelMonitorDailyRollupUpdateOne) SetDeletedAt(v time.Time) *ChannelMonitorDailyRollupUpdateOne {
-	_u.mutation.SetDeletedAt(v)
-	return _u
-}
-
-// SetNillableDeletedAt sets the "deleted_at" field if the given value is not nil.
-func (_u *ChannelMonitorDailyRollupUpdateOne) SetNillableDeletedAt(v *time.Time) *ChannelMonitorDailyRollupUpdateOne {
-	if v != nil {
-		_u.SetDeletedAt(*v)
-	}
-	return _u
-}
-
-// ClearDeletedAt clears the value of the "deleted_at" field.
-func (_u *ChannelMonitorDailyRollupUpdateOne) ClearDeletedAt() *ChannelMonitorDailyRollupUpdateOne {
-	_u.mutation.ClearDeletedAt()
-	return _u
-}
-
 // SetMonitorID sets the "monitor_id" field.
 func (_u *ChannelMonitorDailyRollupUpdateOne) SetMonitorID(v int64) *ChannelMonitorDailyRollupUpdateOne {
 	_u.mutation.SetMonitorID(v)
@@ -823,9 +771,7 @@ func (_u *ChannelMonitorDailyRollupUpdateOne) Select(field string, fields ...str
 
 // Save executes the query and returns the updated ChannelMonitorDailyRollup entity.
 func (_u *ChannelMonitorDailyRollupUpdateOne) Save(ctx context.Context) (*ChannelMonitorDailyRollup, error) {
-	if err := _u.defaults(); err != nil {
-		return nil, err
-	}
+	_u.defaults()
 	return withHooks(ctx, _u.sqlSave, _u.mutation, _u.hooks)
 }
 
@@ -852,15 +798,11 @@ func (_u *ChannelMonitorDailyRollupUpdateOne) ExecX(ctx context.Context) {
 }
 
 // defaults sets the default values of the builder before save.
-func (_u *ChannelMonitorDailyRollupUpdateOne) defaults() error {
+func (_u *ChannelMonitorDailyRollupUpdateOne) defaults() {
 	if _, ok := _u.mutation.ComputedAt(); !ok {
-		if channelmonitordailyrollup.UpdateDefaultComputedAt == nil {
-			return fmt.Errorf("ent: uninitialized channelmonitordailyrollup.UpdateDefaultComputedAt (forgotten import ent/runtime?)")
-		}
 		v := channelmonitordailyrollup.UpdateDefaultComputedAt()
 		_u.mutation.SetComputedAt(v)
 	}
-	return nil
 }
 
 // check runs all checks and user-defined validators on the builder.
@@ -905,12 +847,6 @@ func (_u *ChannelMonitorDailyRollupUpdateOne) sqlSave(ctx context.Context) (_nod
 			}
 		}
 	}
-	if value, ok := _u.mutation.DeletedAt(); ok {
-		_spec.SetField(channelmonitordailyrollup.FieldDeletedAt, field.TypeTime, value)
-	}
-	if _u.mutation.DeletedAtCleared() {
-		_spec.ClearField(channelmonitordailyrollup.FieldDeletedAt, field.TypeTime)
-	}
 	if value, ok := _u.mutation.Model(); ok {
 		_spec.SetField(channelmonitordailyrollup.FieldModel, field.TypeString, value)
 	}