[macOS 26] Desktop sidecar exits silently with code 15 (SIGTERM) after ~2 minutes

Description

Note: This is distinct from #44475 (Windows, exit code 0). This is macOS 26 + Apple Silicon + exit code 15 (SIGTERM) — the sidecar is being killed by the OS/Electron utility process manager, not shutting down cleanly. Related to #27557, #32694, #22630.

Bug Report

Environment:

• macOS: 26.5.2 (25F84) — Sequoia
• Architecture: Apple Silicon (M-series)
• OpenCode Desktop: 1.18.30
• Electron: 42.3.3 (bundled)
• Installation: brew install --cask opencode-desktop

Symptom:

1. Launch OpenCode Desktop
2. Sidecar spawns, logs "server ready" with URL
3. ~2 minutes later: sidecar exits with code 15 (SIGTERM)
4. UI shows "Cannot reach local server. Retrying automatically..."
5. No stderr output, no crash report, no error in main.log between "server ready" and exit

Logs:

Workaround: CLI (opencode) works perfectly — same engine, no Electron utility process.

Related issues: #27557, #32694, #22630

Plugins

None (disabled all plugins, clean install)

OpenCode version

1.18.30 (Desktop) / 1.18.30 (CLI)

Steps to reproduce

1. macOS 26.5.2 on Apple Silicon (M-series)
2. brew install --cask opencode-desktop (v1.18.30)
3. Launch OpenCode.app
4. Wait ~2 minutes
5. Observe sidecar exit code 15, UI shows "Cannot reach local server"

Screenshot and/or share link

Operating System

macOS 26.5.2 (25F84) — Sequoia, Apple Silicon

Terminal

Not applicable (Desktop app bug). CLI works: /opt/homebrew/bin/opencode (Bun 1.4.0)