Windows: bash tool spawns visible cmd.exe window on v1.15.12 (regression) #30315

Description

Since upgrading to v1.15.12 (installed via Chocolatey), each \�ash\ tool call spawns a visible \cmd.exe\ window that flashes for ~0.5s on screen before closing. This did not happen in v1.15.11.

Root Cause

\child_process.spawn\ on Windows defaults to \windowsHide: false, which creates a visible console window. The fix is to pass \windowsHide: true\ (or use the \CREATE_NO_WINDOW\ flag via \detached: true\ + \stdio: 'ignore') when spawning child processes on Windows.

This only affects the native Windows binary (Chocolatey/Scoop install). WSL users are unaffected.

Steps to Reproduce

1. Install OpenCode v1.15.12 on Windows via Chocolatey
2. Run any conversation that uses the \�ash\ tool
3. Observe a \cmd.exe\ window flash briefly for each tool invocation

Expected Behavior

Child processes spawned by the bash tool should be hidden (no visible window). This was the behavior in v1.15.11.

Environment

• Windows 11
• Chocolatey install
• v1.15.12 (regression), v1.15.11 (works correctly)

Additional Context

• No opencode.json configuration can work around this — the issue is internal to the binary.
• All plugins, MCP servers, and custom config were eliminated as causes through systematic testing (zero-plugin, zero-MCP test still flashed).