Add persistent per-user exclusion for duplicate Copilot instruction files

Describe the feature or problem you'd like to solve

Add persistent per-user exclusion for duplicate Copilot instruction files

Proposed solution

Summary:

GitHub Copilot CLI automatically loads supported instruction files such as  CLAUDE.md  and  AGENTS.md . When both contain duplicate or overlapping instructions, Copilot may load the same guidance twice.

The  /instructions  command can disable one file, but the change applies only to the current Copilot CLI session. There is currently no documented persistent, user-specific ignore list for excluding one repository instruction file without modifying the shared repository.

This would be useful for teams sharing repositories across multiple people and agents, including Copilot, CloudA, and Codex. A per-user configuration option to permanently exclude selected instruction files—without affecting other users or agents—would prevent duplicate instruction loading while preserving the repository structure.

Example prompts or workflows

My Claude.md file just mentions/loads Agents.md. All the instruction gets loaded twice and bloat the context..

Additional context

No response

この issue では実装ファイル、テスト、または設定のエントリーポイントが特定されていないため、まず /instructions がセッションの除外をどのように保存しているか、またユーザー設定がどこで読み込まれるかを確認してください。ユーザーごとの永続的な無視リストによって、選択したリポジトリの指示ファイルを、リポジトリを変更したり他のユーザーに影響を与えたりすることなく除外できれば完了です。