Add CLI controls for menu bar app and launch-at-login

[Jing-yilin]

Summary

Add Perch CLI commands for controlling the native macOS menu bar app and launch-at-login behavior.

Today the Swift menu bar app already has LaunchAtLoginManager, and install.sh can opportunistically open a locally available app, but the published perch CLI only supports session management (add/list/done/reopen/doctor). Users should be able to manage the menu bar app from terminal scripts as well.

Proposed CLI

perch menubar start [--app-path <path>]
perch menubar stop
perch menubar status
perch menubar login enable [--app-path <path>]
perch menubar login disable
perch menubar login status

Behavior

perch menubar start

• Locate a local PerchApp executable and launch it.
• Candidate locations, in order:
  1. explicit --app-path
  2. /Applications/Perch.app
  3. repo/dev builds such as App/.build/arm64-apple-macosx/release/PerchApp
  4. repo/dev builds such as App/.build/arm64-apple-macosx/debug/PerchApp
• If already running, exit successfully and print the existing PID.
• If no app is found, exit non-zero with a clear message explaining that the current CLI release does not install PerchApp yet.

perch menubar stop

• Stop the native menu bar app, e.g. by finding/killing PerchApp.
• Exit successfully if it is already stopped.

perch menubar status

• Print whether the menu bar app is running.
• Include PID(s) when running.
• Optional future: --json.

perch menubar login enable

• Create/update ~/Library/LaunchAgents/com.resciencelab.perch.plist using the selected PerchApp executable path.
• Run the equivalent of:
  • launchctl bootout gui/$UID <plist> best-effort
  • launchctl bootstrap gui/$UID <plist>
  • launchctl enable gui/$UID/com.resciencelab.perch
• Validate the executable exists and is executable before writing the plist.

perch menubar login disable

• launchctl bootout gui/$UID ~/Library/LaunchAgents/com.resciencelab.perch.plist best-effort.
• Remove ~/Library/LaunchAgents/com.resciencelab.perch.plist.
• Exit successfully if already disabled.

perch menubar login status

• Report whether the LaunchAgent plist exists.
• Ideally also report the configured executable path.

Non-goals

• Do not bundle or install PerchApp in this issue.
• Do not add signing/notarization/DMG packaging.
• Do not change session storage or Raycast behavior.

Implementation Notes

• The Swift app already has equivalent behavior in App/Sources/PerchAppCore/LaunchAtLoginManager.swift; mirror this behavior in Rust CLI to avoid requiring the app to be running.
• Keep this macOS-only. On unsupported platforms, return a clear error.
• Consider adding a small cli/src/menubar.rs module.

Acceptance Criteria

• perch menubar start starts a local dev/release PerchApp when available.
• perch menubar start --app-path <path> starts the explicit executable path.
• perch menubar start gives actionable error when no app is found.
• perch menubar stop stops the app and is idempotent.
• perch menubar status reports running/stopped state.
• perch menubar login enable --app-path <path> writes a valid LaunchAgent plist and bootstraps it.
• perch menubar login disable removes/unloads the LaunchAgent and is idempotent.
• perch menubar login status reports enabled/disabled state.
• Unit tests cover plist generation, executable validation, and idempotent enable/disable behavior.
• README documents the new commands and notes that current CLI releases do not install PerchApp automatically.

[Jing-yilin]

Completed and released. Menu bar CLI controls and launch-at-login support are available in v0.1.2.