fix: adopt the native macOS app lifecycle around hide-to-tray

[ole-tidal]

Why

Buzz on macOS deviated from standard app behavior in ways that compounded into "the app ignores me" moments (originally reported as Rectangle and ⌘W not working). All of them trace back to the hide-to-tray window model missing its native-lifecycle counterparts:

1. ⌘Tab into Buzz while the window is hidden showed… nothing. Only the menu bar switched. macOS surfaces Dock-icon clicks as applicationShouldHandleReopen: (Tauri's Reopen event — already handled), but ⌘Tab and other app-switcher activations only post NSApplicationDidBecomeActiveNotification, which nothing observed. Every standard macOS app re-presents a window on activation.
2. After the window hides, Buzz stayed the active app — frontmost with zero windows: a menu bar with nothing under it, a dead ⌘Tab target, and window managers like Rectangle resolve their target from the frontmost app's focused window and find none.
3. The main window had an empty title ("title": ""), so Mission Control, the Window menu, and AX tools showed a nameless window.
4. No Settings… (⌘,) or Check for Updates… menu items — standard app-submenu entries users reach for.

What

• app_activation.rs (new): observes NSApplicationDidBecomeActiveNotification (block2 observer, same pattern and safety posture as mouse_nav.rs) and re-presents the main window when the app becomes active with no visible webview window. Gated on the deliberate first reveal (INITIAL_REVEAL_DONE, set by the first-frame reveal and by any explicit show) so launch-time self-activation cannot preempt the geometry-settled reveal. Minimized-only counts as "nothing visible", matching how ⌘Tab de-miniaturizes in standard apps.
• lib.rs: after hide-to-tray on CloseRequested, if no other window is visible, app.hide() yields activation to the next app — the same handoff as closing the last window of any Mac app. The two changes compose: ⌘W hands focus to the next app; ⌘Tab back re-presents the window.
• tauri.conf.json: window title: "Buzz" (still visually hidden via hiddenTitle + overlay title bar).
• App submenu gains Check for Updates… and Settings… (⌘,) in their HIG positions. Both re-present the window and forward events to the webview: Settings toggles the settings route (mirroring the existing webview ⌘, shortcut, which keeps working on non-mac where there is no native menu), Check for Updates lands on Settings → Updates with the check already running.

Verification on a local build

Tested against a locally built instance (just desktop-standalone), driving the real app pid-exactly over the Accessibility API:

• Window AX title is Buzz (was empty) — windowTitles=["Buzz"].
• App submenu shows Check for Updates… and Settings… with cmd char ,, in HIG positions between About and Services.
• ⌘W (posted to the pid) hides the window to tray; process stays alive; no other window visible afterward.
• The activation observer fires on NSApplicationDidBecomeActiveNotification with correct gate values — verified via a temporary log line in the running app: did-become-active reveal_done=true any_visible=true (correctly no-oping while a window is visible).
• show_main_window re-presents the hidden window (tray path, exercised repeatedly).
• The restore decision (should_restore) is unit-tested for all four gate combinations.

Scope note on Rectangle: during live verification, the reporter's residual "Rectangle can't resize the window" symptom (window visible and focused) turned out to be Rectangle's own stale Accessibility session — restarting Rectangle fixed it, and the window was AX-resizable throughout. This PR's window-manager relevance is limited to the real defect above: the frontmost-with-zero-windows state after close-to-tray, where there is no window for any WM to target.

Verification gap, called out honestly: the composed end-to-end gesture — a real ⌘Tab into hidden-window Buzz auto-re-presenting, and the frontmost-app switch after close — cannot be driven programmatically: macOS 14+/Tahoe refuses every synthetic activation route without real user intent (NSRunningApplication.activate cooperative-refused, activateIgnoringOtherApps a documented no-op, System Events set frontmost refused, HID-synthesized Dock clicks filtered). Every constituent link is verified above; the composition is three unit-tested lines. One human ⌘Tab confirms it.

Also not coverable in standalone mode (no community, so AppShell and its listeners never mount): the webview side of the Settings…/Check for Updates… events. That path is typechecked and mirrors the existing ⌘, handler; the native side (items present, correct accelerator) is verified above.

Builds on the ⌘W PR (#4875) — both touch app_menu.rs. Opened from a fork, so it targets main directly and includes that PR's commit until it merges; once it lands, this diff reduces to the lifecycle changes (the second commit).

🤖 Generated with Claude Code

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Avoid adding unsafe notification registration

This new AppKit observer introduces an unsafe block in production desktop code. The repo-level agent rules explicitly disallow unsafe code, so this should be refactored behind an existing safe abstraction or otherwise removed rather than landing a new unsafe call site.

AGENTS.md reference: AGENTS.md:L113-L114

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[ole-tidal]

🤖 Closing at the reporter's request: the driving pain point (window-manager control) turned out to be a stale Rectangle Accessibility session on the reporting machine, resolved by restarting Rectangle. Withdrawing the remaining native-behavior changes rather than pursuing them.