Repo-level instruction files (AGENTS.md/CLAUDE.md/etc.) are not preserved across  /compact

Describe the bug

(Written by Sonnet 5 as we mutually investigated the issue in-session in copilot-cli)
Early in a long session, the agent correctly read and followed a rule in the repo's  AGENTS.md  ("never commit directly to  main ; create a topic branch first"). Mid-session, context compaction occurred. After compaction, the agent committed directly to  main  twice, violating the rule it had followed earlier — it had no indication the rule still applied and never re-read AGENTS.md after compaction.

Root cause: compaction summarizes conversation history, but standing repo instruction files aren't treated as pinned/reloaded — they're just facts that can get compressed away like anything else discussed early in the session.

Suggested fix: on compaction, either (a) re-inject the current contents of any active instruction files (AGENTS.md, CLAUDE.md, copilot-instructions.md, etc.) into the fresh context, or (b) explicitly prompt/require the agent to re-read them before resuming file-editing/git work post-compaction.

Impact: silent policy drift after compaction in any long session touching a repo with custom agent instructions — particularly dangerous for rules like branch protection, since a violation may not surface until a human notices.

Affected version

1.0.80

Steps to reproduce the behavior

1. Open a session in a repo containing an  AGENTS.md  (or  CLAUDE.md / copilot-instructions.md ) with an explicit git-workflow rule, e.g. "never commit directly to  main ; create a topic branch first."
2. Have the agent read that file early in the session (directly, or incidentally via a  view / grep  call) and perform at least one commit that correctly follows the rule (confirms the rule was live in context).
3. Continue the session with enough unrelated work/turns that automatic or manual ( /compact ) context compaction occurs at least once.
4. After compaction, ask the agent to make further code changes and commit them in the same repo, without re-mentioning the branching rule.
5. Observe: the agent commits directly to the currently-checked-out default branch (e.g.  main ), violating the rule it followed correctly in step 2 — with no re-read of  AGENTS.md  and no acknowledgment that a repo policy exists.

Expected behavior

The rule from  AGENTS.md  continues to be honored after compaction, either because the file's contents are re-injected into context at compaction time, or because the agent is prompted to re-read active instruction files before resuming work in that repo.

Actual: the rule silently stops being followed post-compaction, with no error, warning, or indication to the user that it had been dropped — only surfaced when the human happened to notice the resulting commits.

Additional context

No response

该 issue 指出了活动指令文件（AGENTS.md、CLAUDE.md 和 copilot-instructions.md）以及 /compact 流程；首先跟踪压缩如何恢复会话，以及这些文件最初是如何加载的。复现编号工作流，然后验证压缩后的工作仍然遵循分支规则，或明确重新加载这些文件。