opencode config path on Windows uses %APPDATA% instead of ~/.config/opencode/

[fucknoobhanzo]

Describe the bug

On Windows, CodeGraph's opencode installer target writes config to %APPDATA%\opencode\ instead of ~/.config/opencode\. However, opencode uses ~/.config/opencode/ on all platforms including Windows, so the MCP config is never picked up.

This is a known issue affecting multiple projects — see:

• Documentation mismatch: Config path on Windows uses %APPDATA% instead of ~/.config NoeFabris/opencode-antigravity-auth#265
• docs: Windows config path is incorrect - plugin uses %APPDATA%, not ~/.config NoeFabris/opencode-antigravity-auth#251
• [Bug]: incorrect path for opencode on windows vercel-labs/skills#208

To Reproduce

1. Install CodeGraph globally on Windows
2. Run codegraph init -i in a project
3. Select opencode as a target
4. Config is written to %APPDATA%\opencode\ (wrong location)
5. OpenCode does not detect CodeGraph MCP server

Expected behavior

Config should be written to ~/.config/opencode/opencode.jsonc on all platforms including Windows.

Environment

• OS: Windows
• CodeGraph version: latest
• OpenCode config path: C:\Users\<user>\.config\opencode\opencode.jsonc

Workaround

Manually create/edit ~/.config/opencode/opencode.jsonc:

{
  "mcp": {
    "codegraph": {
      "type": "local",
      "command": ["<path-to-codegraph-binary>", "serve", "--mcp"],
      "enabled": true
    }
  }
}