docs(performance): list the welcome-state grid loop and the M3U player EPG clock

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/architecture/idle-work-audit-2026-09.md

@@ -223,6 +223,8 @@ user who leaves that screen open pays them indefinitely, minimized included.
 | [downloads.component.ts:223](../../libs/portal/downloads/feature/src/lib/downloads.component.ts), [recording-queue.component.ts:88](../../libs/portal/downloads/feature/src/lib/recording-queue.component.ts) | Recordings reload and elapsed-time tick | 15 s / 1 s while recordings are active and the page is open | `loadRecordings()` IPC and SQL / CD tick | **Partly.** Downloads are already push-based, so recordings could be too. | Static | **Own thread.** Push recording state like `onDownloadsUpdate`. |
 | [controls-stream-stats.ts:42](../../libs/ui/playback/src/lib/player-controls/controls-stream-stats.ts) | Stream-info sampling | 1 s, only while the stream-info popover is open; `stop()` clears it when the popover closes | CD tick each | Yes (a closed popover costs nothing) | Static | None |
 | 30 s EPG clocks in the Xtream, Stalker, EPG guide and unified live views | "Now" clocks for progress and the current programme | 30 s for as long as their route is open | CD tick each | Yes while visible | Static | Cover with the throttling thread (pause on hidden). |
+| [empty-state.welcome-dashboard.scss:58](../../libs/playlist/shared/ui/src/lib/recent-playlists/empty-state/empty-state.welcome-dashboard.scss) (`gridMove`, keyframes in `empty-state.component.scss:169`) | First-run dashboard with no playlists: the welcome state's `::before` grid drifts via an infinite `transform` animation | Continuous (60 s loop) while the empty dashboard is shown; the reduced-motion block does not stop the pseudo-element | Compositor and GPU frames only, no main-thread layout (not measured) | **Partly.** Decorative; a first-run screen left open keeps the GPU busy, and reduced motion should stop it. | Static | **Own thread** (small): stop the `::before` animation under `prefers-reduced-motion`, and consider pausing it while hidden (throttling stops compositor frames in a hidden window once #1724 lands). |
+| [video-player.component.ts:790](../../libs/playlist/m3u/feature-player/src/lib/video-player/video-player.component.ts) `epgNowMs` | M3U playlist view: refreshes "now" for EPG state, unconditionally, separate from the channel-list timers above | 30 s while an M3U playlist route is open, with or without an active channel | A signal write and an app-wide CD tick | **Partly.** Needed while a programme is shown; not with no channel selected. | Static | Cover with the throttling thread (pause on hidden), and start it only while a channel with EPG is active. |
 
 ## Related observation