[FEATURE] UX: /compact should preserve original conversation in history and continue in a new session

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

When /compact is triggered (manually or automatically), the current behavior compacts the conversation in place: the original messages are replaced by a summary within the same session. The original JSONL file is preserved on disk, but it becomes inaccessible from the Claude Code UI — it no longer appears as a distinct entry in the conversation history.

Why this matters:

The compaction summary is necessarily lossy. In a real use case today, a detail from before compaction was missing from the summary — and the only way to recover it was to manually locate the UUID-named JSONL file on disk and parse it. That is not a reasonable expectation for most users.

The proposed behavior would make compaction feel like turning a page, not erasing one.

Current workaround:

The user can manually note the JSONL path before compacting and provide it explicitly in the new session, but this requires knowing where the files are stored and is not discoverable.

Proposed Solution

Expected / proposed behavior:

The original conversation remains visible in the history as a closed/archived session.
A new session is automatically created, pre-seeded with the compacted summary as context.
The user can navigate back to the original session if they need to review what was said before compaction.

Alternative Solutions

_No response_

Priority

High - Significant impact on productivity

Feature Category

Interactive mode (TUI)

Use Case Example

_No response_

Additional Context

_No response_