fix(home): easyeffects waits for a live tray host, not waybar.service

The tray-race guard (wwmm/easyeffects#4636) ordered the unit
After=waybar.service — inert here: Nomarchy's waybar runs from the
nomarchy-waybar supervisor (Hyprland exec-once), never as a systemd
unit, so the icon vanished whenever easyeffects won the boot race
(seen on TuringMachine 2026-07-11). Gate ExecStartPre on the SNI
watcher's IsStatusNotifierHostRegistered with a 30s timeout, non-fatal
so audio processing still starts on tray-less setups.

Also: #89 inventory narrowed by Bernardo's visual verdict — Telegram/
ZapZap fine; offenders are EasyEffects (slice 2) and Signal (slice 3).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

agent/BACKLOG.md

@@ -75,6 +75,15 @@ Slices:
    | Signal | `Signal_status_icon_1` (generated, not a real theme name) | yes | **pixmap** — slice 3 |
    | ZapZap | *(empty)* | yes | **pixmap** — slice 3; check its own tray-style setting first |
    | EasyEffects 8 | `com.github.wwmm.easyeffects` (prior T14s finding) | — | **name-based**; NB `--gapplication-service` alone registers no SNI |
+
+   **Bernardo's visual verdict (T14s, 2026-07-11):** Telegram and ZapZap
+   already read fine on the bar — out of scope. The offenders are
+   **EasyEffects** (slice 2: name-based override) and **Signal**
+   (slice 3: pixmap; check for an app-side tray option, else document).
+   Related fix shipped same day: easyeffects.service now *waits for a
+   registered tray host* before starting (the old After=waybar.service
+   ordering was inert — waybar is supervisor-run, not a unit), so the
+   icon no longer vanishes on unlucky boot order.
 2. **Override layer:** an HM-managed shadow icon dir that wins the XDG
    lookup for the session icon theme (e.g. `xdg.dataFile
    "icons/<theme-iconset>/…"` shadowing the store copy, or a