fix(tray): Linux tray icon duplicates and dead menus on minimize-to-tray toggle

[jing2uo]

Description

On Linux, toggling Settings → General → "Minimize to tray" off and on again
leaves a dead icon in the system tray every time. After a few toggles the tray
shows a stack of Folo icons; each opens a context menu but only the newest one's
menu does anything. The pile only clears when Folo fully quits.

Root cause: setTrayConfig(false) calls tray.destroy(). On a
StatusNotifierItem host (waybar, KDE Plasma, …) that does not remove the icon —
Chromium's StatusIconLinuxDbus registers the item by object path on the
process-wide shared session-bus connection and, on teardown, un-exports its own
objects but never tells org.kde.StatusNotifierWatcher the item is gone. The
connection name outlives the tray, so the host gets no NameOwnerChanged and
keeps a dead icon. Re-enabling then calls new Tray() again and Chromium
registers a fresh /org/chromium/StatusNotifierItem/<n+1>, stacking another.

Fix (commit 1): on Linux, keep the single Tray instance for the app's
lifetime instead of destroying/recreating it on the toggle. registerAppTray()
already guards new Tray() behind if (tray), and the window close handler
reads getTrayConfig() on every close, so a tray icon that outlives a disabled
setting is inert.

Follow-up (commit 2): the icon genuinely can't be removed from a running
process on Linux (Electron's Tray has no hide/visibility API), so
setTrayConfig now returns whether a restart is needed (true only when
disabling on Linux with a tray present). settings.setMinimizeToTray forwards
that and the renderer shows a toast with a "Restart now" action wired to a new
app.relaunch IPC. Enabling the tray, and all behavior on macOS/Windows, is
unchanged and takes effect immediately.

The real fix belongs upstream in Chromium/Electron (StatusIconLinuxDbus should
own a per-item well-known bus name and release it on teardown so hosts get
NameOwnerChanged); this is a workaround until then.

PR Type

• Bugfix
• Feature (minor: the "restart to remove the tray icon" prompt)

Screenshots (if UI change)

Demo Video (if new feature)

Linked Issues

Fixes #3940
Related: #4985, #3207

Additional context

Verified on Debian + Hyprland + waybar (Flatpak build, 1.13.0 / Electron 43.1.0).
D-Bus evidence: RegisteredStatusNotifierItems held four
:1.XXX/org/chromium/StatusNotifierItem/1..4 entries from a single process;
busctl --user tree showed only /4 actually exported; dbus-monitor showed
one RegisterStatusNotifierItem per toggle and never an unregister; on quit,
the host dropped all of them at once.

For review — the trade-off in commit 2: after disabling on Linux the icon
lingers until the app restarts (the toast's "Restart now" is optional; ignoring
it just leaves one inert icon, no stacking). Happy to switch to auto-relaunch or
drop the prompt entirely. The two new i18n strings fall back to en in other
locales.

Changelog

• I have updated the changelog/next.md with my changes.
  (apps/desktop/changelog/next.md — desktop-only change)

[jing2uo]

@DIYgod 这个方便看下不~ 问题是: linux 下每次点关闭到托盘, 都会多一个托盘图标, 反复点的话会出一堆但只有最新那个可以点击. 必须关闭应用才能正常.

[github-actions]

Bot detected the issue body's language is not English, translate it automatically. 👯👭🏻🧑‍🤝‍🧑👫🧑🏿‍🤝‍🧑🏻👩🏾‍🤝‍👨🏿👬🏿

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@DIYgod Is this convenient? The problem is: every time you click Close to the tray under Linux, there will be an extra tray icon. If you click it repeatedly, a bunch of them will appear, but only the latest one can be clicked. You must close the application to normal.