výkon: pomalejší polling (60/15/120 s) a dynamický limit telemetrie 15m

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/src/hooks/useDashboardData.ts

@@ -25,8 +25,11 @@ import type {
 } from '../types/ems'
 import type { PlanningIntervalDto } from '../types/plan'
 
-const POLL_FULL_MS = 30_000
-const POLL_LIVE_MS = 5_000
+const POLL_FULL_MS = 60_000
+const POLL_LIVE_MS = 15_000
+
+/** Limit řádků vw_telemetry_15m_7d: jen okno zpět (s rezervou), ne celých 7 dní. */
+const TELEMETRY_15M_LIMIT = String(Math.ceil(SLOT_COUNT_BACK * 1.2))
 
 function parseNum(v: string | number | null | undefined): number | null {
   if (v == null) return null
@@ -211,8 +214,9 @@ export function useDashboardData(siteId: number | null) {
         getJson<SiteStatusRow[]>('/vw_site_status', { site_id: `eq.${siteId}` }),
         getJson<Telemetry15m7dRow[]>('/vw_telemetry_15m_7d', {
           site_id: `eq.${siteId}`,
+          slot_start: `gte.${new Date(windowStart).toISOString()}`,
           order: 'slot_start.asc',
-          limit: '1000',
+          limit: TELEMETRY_15M_LIMIT,
         }),
         getJson<AuditTodayHourlyRow[]>('/vw_audit_today_hourly', {
           site_id: `eq.${siteId}`,

frontend/src/hooks/useFullStatus.ts

@@ -3,7 +3,7 @@ import { useCallback, useEffect, useState } from 'react'
 import { getSiteStatusFull } from '../api/backend'
 import type { FullStatusResponse } from '../types/fullStatus'
 
-const POLL_MS = 60_000
+const POLL_MS = 120_000
 
 export function useFullStatus(siteId: number | null) {
   const [data, setData] = useState<FullStatusResponse | null>(null)