[Bug] Production Desktop 1.18.15 still cannot load Bun-target plugins (oh-my-openagent); V2 sidecar not bundled

Description

On the latest production OpenCode Desktop (v1.18.15, Windows 11 x64), Bun-target plugins still fail to load silently. In my case oh-my-openagent v4.19.4 (latest) is installed in %USERPROFILE%\.config\opencode\opencode.jsonc:

{ "plugin": ["oh-my-openagent"] }

The Desktop agent picker only shows built-in agents (build, plan, ...). None of the plugin-registered agents (Sisyphus etc.) appear, and there is no visible error in the UI.

Evidence

• The plugin's private log (%TEMP%\oh-my-opencode.log) receives zero new entries after the Desktop sidecar starts — the plugin is never instantiated at all. Same config under the CLI (Bun runtime) loads the plugin fine.
• Desktop server.log contains no plugin error at all (silent drop).
• opencode.global.dat / session state shows only native agents.
• Bun 1.3.14 is installed and on PATH; spawnSync('bun') resolves fine.

Key new information (vs #25880, #35573)

The v1.18.9 changelog says: "Added an opt-in V2 desktop sidecar backed by the bundled CLI service." However, in the production build (1.18.14/1.18.15) that V2 sidecar is not usable: setting OPENCODE_SIDECAR_V2=1 fails immediately with ENOENT because the v2 CLI binary is not bundled in the shipped build — same as reported in #40980. So production users have no way to get the Bun-based sidecar today.

Expected behavior

Production Desktop builds should either:

1. Ship the V2 sidecar (bundled CLI service) so Bun-target plugins load, or
2. Provide a runtime selector for the sidecar (Bun vs Node), or
3. Document that Bun-target plugins are unsupported in Desktop until the V2 sidecar ships, with a clear startup warning instead of a silent drop.

Environment

• OS: Windows 11 x64
• OpenCode Desktop: 1.18.15 (latest production)
• Plugin: oh-my-openagent 4.19.4 (latest)
• Bun: 1.3.14

Related issues

• #25880 — Desktop v1.14.39: Bun-target plugins fail to load (Node.js sidecar lacks Bun APIs)
• #35573 — Native built-in file tools return "Bun is not defined" under Desktop
• #40980 — V2 sidecar unavailable in production build (ENOENT)
• #33366 — Desktop custom tools fail with Bun workspace deps