[v1.1.1] Missing "Universal / Other tools" option in init: How to configure for custom/proprietary AI plugins?

[Happy-Goose]

Describe the question/issue
I have recently upgraded my project from openspec v0.17.2 to v1.1.1.

In v0.17, when running openspec init, there was an option labeled:

Other tools (use Universal AGENTS.md for Amp, VS Code, GitHub Copilot, ..)

I relied on this option because I use a proprietary corporate AI plugin (similar to GitHub Copilot/Turing) inside VS Code. My plugin does not have a specific "Agent Skill" integration like Cline or Cursor, but it can read the generic AGENTS.md (or instructions.md) context to help me generate specs.

The Problem
After upgrading to v1.1.1 and running openspec init, the specific "Universal" or "Other tools" option seems to be missing. The list is now very specific (e.g., Cline, Cursor, GitHub Copilot, Windsurf, etc.).

My Question
For users using custom or proprietary AI assistants that just need a generic System Prompt (similar to the old Universal AGENTS.md):

1. Which option should we select in the new v1.0 menu?
2. Is the "GitHub Copilot" option the intended replacement for a generic "System Prompt" generation (even if we are not strictly using Copilot)?

Environment

• OpenSpec version: v1.1.1
• OS: macOS
• Editor: VS Code with proprietary AI plugin

Expected behavior
I expected to find a "Generic", "Universal", or "Manual" option for tools not listed in the supported integrations.

Thanks for the great work on v1.0!