feat(toolpath-desktop): menu-bar Quick View for live agent activity

[eliothedeman]

Summary

• Adds a macOS tray icon to toolpath-desktop that shows live activity across all five agent-conversation providers (toolpath-claude, -gemini, -codex, -opencode, -pi). A background thread polls every 30s, classifies sessions as active (last activity <2 min) or recent (<24h), and updates the tray title with a count.
• Left-clicking the tray opens a small popover window listing recent sessions. Clicking a claude or pi session derives its trace via the existing derive_* IPC commands and opens it in the main window's preview route, via a trace:opened event. Rows for gemini/codex/opencode show for activity tracking but are disabled until their desktop-side derive commands land.
• The popover has an "Open Toolpath" button that shows + focuses the main window. The tray menu has Open / Refresh now / Quit.

Implementation notes

• New src/tray.rs owns the tray icon, menu, poller thread, and three IPC commands: tray_stats_now, tray_open_main, tray_open_trace.
• New popover window uses a second Vite entry (popover.html → src/popover.ts → routes/Popover.svelte); vite.config.ts grows a second rollup input.
• Adds tauri-plugin-positioner (for anchoring the popover to the tray) and toolpath-gemini/-codex/-opencode deps (for the stats poller).
• The app stays a normal Dock-icon GUI app — ActivationPolicy::Accessory was tried and reverted because macOS tiling window managers (yabai, Amethyst) stop managing accessory windows. The tray is a secondary surface, like Slack/Linear.

Test plan

• cargo test -p toolpath-desktop — 17/17 pass (two existing + four new for bucket logic, stats smoke, basename slug, session-id truncation)
• cargo clippy -p toolpath-desktop --tests -- -D warnings
• bun run check in frontend/ — 0 errors (4 pre-existing warnings in unrelated files)
• bun run build — produces both index.html and popover.html bundles
• Manual: cargo tauri dev, verify tray appears, popover opens on left-click, activity counts update, clicking a claude/pi session opens the preview
• Manual: verify main window is still tiled by the user's window manager (yabai/Amethyst)

[github-actions]

🔍 Preview deployed: https://8786e645.toolpath.pages.dev