Homebrew support for OpenCode v2 Desktop

Description

OpenCode v2 CLI is now available through the official Homebrew tap:

brew install anomalyco/tap/opencode-v2

This currently installs OpenCode v2.0.11 and addresses the CLI side of the Homebrew distribution discussed in #36279.

However, there is currently no equivalent Homebrew installation/update path for the OpenCode v2 Desktop application.

The existing Homebrew cask:

brew install --cask opencode-desktop

still installs OpenCode Desktop v1.18.31, while OpenCode Desktop v2 builds are already available through the official OpenCode distribution.

Current state

• OpenCode v2 CLI via Homebrew: v2.0.11 (anomalyco/tap/opencode-v2)
• OpenCode Desktop via Homebrew: v1.18.31 (opencode-desktop)
• OpenCode Desktop v2: available outside Homebrew (https://opencode.ai/v2/docs/)

Request

Please provide an official Homebrew installation/update path for OpenCode v2 Desktop as well.

Ideally, users should be able to manage both components consistently through Homebrew, for example:

• CLI → anomalyco/tap/opencode-v2
• Desktop → corresponding v2 cask

This would also avoid accidentally installing the v1 Desktop client alongside the v2 CLI when following a Homebrew-based setup.

Related: #36279

Review the existing opencode-desktop cask and the anomalyco/tap/opencode-v2 installation path first; the issue does not name repository files. Compare them with the OpenCode v2 Desktop distribution documented at opencode.ai/v2/docs/, and define a cask or update path that installs the v2 Desktop application instead of v1.18.31.