feat(channel-monitor): redesign user dashboard as card grid

Reference check-cx UI: INTELLIGENCE MONITOR hero + 3-column card grid
with 60-point timeline bars.

Backend:
- Add PrimaryPingLatencyMs + Timeline[60] to UserMonitorView
- ListRecentHistoryForMonitors: batch CTE + ROW_NUMBER() window query
- indexLatestByModel / indexAvailabilityByModel helpers

Frontend:
- 7 new components: ProviderIcon, MonitorMetricPair, MonitorAvailabilityRow,
  MonitorTimeline, MonitorHero, MonitorCard, MonitorCardGrid
- ChannelStatusView 381→~180 lines (delegated to subcomponents)
- AbortController reload concurrency protection
- HSL 0-120° availability color mapping
- Replace emoji with Icon component (bolt / globe)
- i18n: monitorCommon.* shared namespace, channelStatus.hero.*

Bump VERSION to 0.1.114.24

frontend/src/api/channelMonitor.ts

@@ -14,6 +14,13 @@ export interface UserMonitorExtraModel {
   latency_ms: number | null
 }
 
+export interface MonitorTimelinePoint {
+  status: MonitorStatus
+  latency_ms: number | null
+  ping_latency_ms: number | null
+  checked_at: string
+}
+
 export interface UserMonitorView {
   id: number
   name: string
@@ -22,8 +29,10 @@ export interface UserMonitorView {
   primary_model: string
   primary_status: MonitorStatus
   primary_latency_ms: number | null
+  primary_ping_latency_ms: number | null
   availability_7d: number
   extra_models: UserMonitorExtraModel[]
+  timeline: MonitorTimelinePoint[]
 }
 
 export interface UserMonitorListResponse {