Umbrella issue. Tracks the background-monitoring + system-tray feature set as a whole. The work is split into focused child issues that each ship independently; this issue is the discussion thread and progress board for the family.

Summary

Allow HardwareVisualizer to keep collecting metrics after the main window is closed, with a system-tray entry point to reopen the app, pause/resume collection, or quit cleanly. Originally written as a single feature issue; now restructured into discrete shippable units.

Motivation

A hardware monitor only delivers value while it is running. Today the app stops monitoring when the window is closed. Background mode + a tray entry turns the app into a passive, always-on tool — the same value pattern as Stats (macOS) and Open Hardware Monitor (Windows). It also unblocks #1401 (live tray widget) by making collection independent of window visibility.

Children

• feat(app): system tray adapter — Open / Quit menu skeleton #1422 [A] — feat(app): tray adapter — Open / Quit menu skeleton.
  • Always-on tray icon, Open / Quit, left-click restores window. AppIndicator caveats documented.
• feat: close-to-tray setting + first-run dialog #1423 [B] — feat: close-to-tray setting + first-run dialog.
  • Persisted setting replaces the Phase 5 HARDVIZ_CLOSE_TO_BACKGROUND env var. First-run dialog. Linux fallback when tray fails. macOS Dock policy stays Regular (LSUIElement is out of scope).
• feat: pause / resume monitoring (tray menu + runtime wiring) #1424 [C] — feat: pause / resume monitoring.
  • Tray menu entries, runtime wiring of MonitoringState::Paused (the Phase 5 state machine value that's currently a stub).

Related

• feat: live hardware metrics in system tray / menu bar (Stats-like widget) #1401 [D] — feat: live hardware metrics in the tray (Stats-like widget). Depends only on feat(app): system tray adapter — Open / Quit menu skeleton #1422 ([A]); does not require [B] or [C] to land first.
• Epic: split backend into Tauri-independent Core and thin App adapters #1402 — Core/App split Epic. Phase 5 (refactor(core): Phase 5 — introduce MonitoringState machine and decouple lifecycle from window close #1408 / merged in refactor(core): Phase 5 — MonitoringState machine and lifecycle decoupling (#1408) #1420) shipped the lifecycle decoupling and MonitoringState machine that the children above consume.
• refactor(app): Phase 6 — add tray adapter skeleton (Open / Quit menu only) #1409 — closed; rescoped to feat(app): system tray adapter — Open / Quit menu skeleton #1422.

Future follow-ups (not in scope of this umbrella; track separately when needed)

• Launch on login — depends on [B]; trivial via tauri-plugin-autostart once the persisted setting exists.
• Reduced polling frequency while backgrounded — needs a config knob and per-mode collector cadence; not blocking the v1 UX.
• Threshold-based notifications — adjacent feature; would consume the same EventBus.
• macOS LSUIElement / Dock-hidden mode — opt-in accessory app behavior; tracked separately if user demand surfaces.

Platform Notes

Background-mode UX is highest-value on Windows; macOS works the same way once tray is registered. Linux tray support varies by desktop environment — [B] handles the fallback so users on AppIndicator-less environments are not stranded.

Acceptance Criteria (umbrella)

This issue is "done" when [A]+[B]+[C] are merged. Each child carries its own DoD. From a user-visible standpoint the umbrella ships when:

• Closing the main window does not stop monitoring (when the user has opted in).
• The app remains accessible from the system tray.
• The tray menu can reopen the main window.
• The tray menu can pause and resume monitoring.
• The tray menu can fully quit the app.
• Historical data continues to be recorded while the window is closed.
• The close behavior is explained to users clearly at least once (first-run dialog).
• Setting persists across restarts.

Open questions

• First-run dialog default (Continue vs Quit highlighted)?
• Should Pause also pause history persistence, or only sensor collection? Decided in [C]: only collection; the archive worker stays subscribed and is naturally idle when no snapshots flow.
• Linux: do we accept icon-only / no-color fallback on AppIndicator-less environments, or document an extension as a soft requirement? Decided in [B]: graceful fallback to "quit on close" with a banner; we do not require an extension.