fix(channel-monitor-v2): clear CI lint and align trend axis with range zoom

Fix golangci unused/gofmt on the gentle-backfill path. Plot matrix and
line-chart X axes on the selected [requested_start, requested_end)
window (empty slots while backfill lags), and let plain mouse-wheel zoom
narrow the visible interval so pulse blocks grow wider.

backend/internal/repository/channel_monitor_v2_repo.go

@@ -1019,6 +1019,7 @@ func (r *channelMonitorV2Repository) loadCoverage(ctx context.Context, filter se
 	if !wm.HasData || wm.DataThrough.IsZero() || wm.LastSuccessfulAt.IsZero() {
 		return &service.ChannelMonitorV2Coverage{
 			RequestedStart:        filter.Start,
+			RequestedEnd:          filter.End,
 			CoverageStart:         filter.End,
 			DataThrough:           filter.Start,
 			ComputedAt:            time.Time{},
@@ -1053,6 +1054,7 @@ func (r *channelMonitorV2Repository) loadCoverage(ctx context.Context, filter se
 	// minute-level lag would otherwise always show "partial historical coverage".
 	return &service.ChannelMonitorV2Coverage{
 		RequestedStart:        filter.Start,
+		RequestedEnd:          filter.End,
 		CoverageStart:         coverageStart,
 		DataThrough:           through,
 		ComputedAt:            computedAt,

backend/internal/service/channel_monitor_v2.go

@@ -149,7 +149,11 @@ type ChannelMonitorV2HealthThresholds struct {
 }
 
 type ChannelMonitorV2Coverage struct {
-	RequestedStart        time.Time `json:"requested_start"`
+	RequestedStart time.Time `json:"requested_start"`
+	// RequestedEnd is the exclusive upper bound of the UI-selected window
+	// (filter.End). Charts/matrices should plot [RequestedStart, RequestedEnd)
+	// even when CoverageStart is later (partial backfill).
+	RequestedEnd          time.Time `json:"requested_end"`
 	CoverageStart         time.Time `json:"coverage_start"`
 	DataThrough           time.Time `json:"data_through"`
 	ComputedAt            time.Time `json:"computed_at"`

backend/internal/service/channel_monitor_v2_aggregator.go

@@ -15,9 +15,6 @@ const (
 	// Retention walks back to the longest stored tier (1d rollup = 90d). Per-tier
 	// prune in the repository drops short-lived 1m/user/hist facts earlier.
 	channelMonitorV2RetentionMax = 90 * 24 * time.Hour
-	// Product bootstrap goal: fill the UI ranges 90m / 24h / 7d / 30d first.
-	// Banner hides once coveredFrom reaches this depth; 90d retention continues silently.
-	channelMonitorV2BootstrapWindow = ChannelMonitorV2BootstrapProductWindow
 	// First tick after upgrade prioritizes the default 90m view (with small padding).
 	channelMonitorV2BootstrapFirst = 2 * time.Hour
 	// Always refresh a small trailing window so late writes land without
@@ -188,23 +185,6 @@ func (s *ChannelMonitorV2Aggregator) loop() {
 	}
 }
 
-func (s *ChannelMonitorV2Aggregator) bootstrapActive() bool {
-	s.mu.Lock()
-	defer s.mu.Unlock()
-	if !s.cursorLoaded {
-		return true
-	}
-	if !s.hasAggregated {
-		return true
-	}
-	if s.backfillFailures >= 3 {
-		return false
-	}
-	now := time.Now().UTC().Truncate(time.Minute)
-	target := now.Add(-channelMonitorV2BootstrapWindow)
-	return s.backfillAt.IsZero() || s.backfillAt.After(target)
-}
-
 func (s *ChannelMonitorV2Aggregator) passiveAggregationAllowed(ctx context.Context) bool {
 	if s == nil || s.settings == nil {
 		// Fail closed without settings: do not aggregate under ambiguous mode.

backend/internal/service/setting_parse.go

@@ -787,9 +787,9 @@ func (s *SettingService) parseSettings(settings map[string]string) *SystemSettin
 	result.ChannelMonitorDefaultIntervalSeconds = parseChannelMonitorInterval(
 		settings[SettingKeyChannelMonitorDefaultIntervalSeconds],
 	)
-// 默认隐藏吞吐（迁移 206 的隐私默认）：未配置时必须与 setting_public.go 的
-// 公开读取路径给出同一个值，否则管理端看到“未隐藏”而用户端实际已隐藏。
-result.ChannelMonitorHideThroughput = !isFalseSettingValue(settings[SettingKeyChannelMonitorHideThroughput])
+	// 默认隐藏吞吐（迁移 206 的隐私默认）：未配置时必须与 setting_public.go 的
+	// 公开读取路径给出同一个值，否则管理端看到“未隐藏”而用户端实际已隐藏。
+	result.ChannelMonitorHideThroughput = !isFalseSettingValue(settings[SettingKeyChannelMonitorHideThroughput])
 
 	// Available channels feature (default: disabled; strict true)
 	result.AvailableChannelsEnabled = settings[SettingKeyAvailableChannelsEnabled] == "true"