OpenCode Desktop's Electron sidecar runtime can omit Bun's ctx.$ helper.
The sender previously called ctx.$ unconditionally, throwing
TypeError: ctx.$ is not a function as unhandledRejection and crashing
the sidecar with exit code 1.
Add a runtime guard at every call site, falling back to Node.js
child_process.execFile (with windowsHide: true) when ctx.$ is missing.
The Bun ctx.$ path remains preferred when available. Every notification
path is wrapped in try/catch so no failure escapes as unhandledRejection.
Fixes#4128Fixes#4061
Add cmux as the highest-priority notification provider on macOS.
cmux delivers notifications via native UNUserNotificationCenter,
properly attributed to the cmux app instead of Script Editor.
Notification priority: cmux > terminal-notifier > osascript
Tests cover the full fallback chain:
- cmux available: uses cmux, skips others
- cmux fails: falls back to terminal-notifier
- cmux + terminal-notifier fail: falls back to osascript
- cmux not available: skips to terminal-notifier
Fixes#3628
YeonGyu-Kim