Desktop v0.1.4: fix dead tray click, template icon, and first-run window

[ericflo]

Why

The v0.1.3 macOS install was unusable on first launch:

• The tray icon rendered as a solid black square in the menu bar
• Left-clicking it did nothing — totally dead UI
• No window ever appeared on launch — only the macOS About menu worked

Three stacked bugs caused it. This PR fixes all three and cuts desktop v0.1.4.

What

1. Real monochrome template tray icon

tauri.conf.json declared iconAsTemplate: true but pointed iconPath at icons/icon.png, which is the full-color 1024×1024 carrier-pigeon brand mark (cream rounded-square background, deep slate-blue silhouette). macOS template icons must be monochrome (black + alpha) — anything else renders as a solid black blob.

Added two new assets derived from the existing brand mark:

• crates/modelrelay-desktop/icons/tray-icon.png (22×22)
• crates/modelrelay-desktop/icons/tray-icon@2x.png (44×44)

Both are pure black RGB with alpha derived from a contrast-pushed luminance inversion of the source mark, then auto-cropped to the silhouette bbox and padded ~10% so the pigeon fills the tray frame at small sizes. trayIcon.iconPath now points at icons/tray-icon.png. Bundle icon references (bundle.icon) are unchanged — those use the full-color icons and are correct.

2. Tray click reliability

TrayIconBuilder had no left-click affordance. On macOS in Tauri 2.10, that means left-click is a dead no-op unless one of:

• .show_menu_on_left_click(true) — pops the menu on left-click
• .on_tray_icon_event(...) — gives you the click event to react to

Added both:

• show_menu_on_left_click(true) so the menu opens on left-click like users expect.
• A belt-and-suspenders on_tray_icon_event handler that, on TrayIconEvent::Click { button: Left, button_state: Up, .. }, shows + focuses the main window. Even if the menu fails to pop on some platform, the tray is never a dead UI element.

3. First-run window visibility

The single window in tauri.conf.json has visible: false and main.rs::setup() never called window.show(). So if the tray was broken (see #1 + #2), the user never saw any UI.

The setup now shows + focuses the main window on launch unless the user is the returning silent-tray case (auto_start enabled AND worker_secret non-empty). This means:

• First launch: window appears so the onboarding wizard is reachable.
• Returning user without auto_start: window appears.
• Returning user with auto_start and a saved secret: silent tray launch as before.

4. Version bump

• crates/modelrelay-desktop/Cargo.toml: 0.1.3 → 0.1.4
• crates/modelrelay-desktop/tauri.conf.json: 0.1.3 → 0.1.4
• Cargo.lock: cargo update -p modelrelay-desktop --precise 0.1.4
• CHANGELOG.md: new Desktop 0.1.4 entry summarizing the three fixes

Validation

• cargo fmt --check -p modelrelay-desktop — clean
• cargo check --workspace --exclude modelrelay-desktop — clean
• Tauri 2.10 API verified against tauri-2.10.3/src/tray/mod.rs in the local cargo cache: show_menu_on_left_click, on_tray_icon_event, TrayIconEvent::Click { button, button_state, .. }, MouseButton::Left, MouseButtonState::Up, and TrayIcon::app_handle() all exist with the expected signatures.
• The modelrelay-desktop crate cannot be cargo-checked locally because GTK/webkit2gtk system libs are absent in the dev environment; CI runners on macOS / Windows / Linux will perform the full build.

Tagging

This PR does not tag desktop-v0.1.4. Tag after verifying the diff looks right.