Persist live comments so a Hunk review session can be continued after quit

[benvinegar]

Problem

If you quit Hunk, you lose your live agent comments for that review session.

That makes longer review workflows fragile: comments are useful precisely because they accumulate context, but today that context appears to be tied to the lifetime of the live session.

Current implementation notes

Relevant pieces:

• feat: add live session comment lifecycle #53 — feat: add live session comment lifecycle
• src/mcp/sessionRegistration.ts
  • createInitialSessionSnapshot() starts each session with liveComments: []
• src/mcp/daemonState.ts
  • session snapshots are tracked in daemon memory while the session is connected

That is great for live coordination, but there does not appear to be a persistence / restore path for comments or session state after the TUI exits.

Desired behavior

There should be a way to continue a previous Hunk review session and restore its live comments (and ideally related state like the focused file/hunk).

The UX could be something like:

• hunk --continue-session
• hunk session resume ...
• or another explicit restore flow

Scope suggestions

Persist at least:

• review input identity (working tree / show ref / patch file / etc.)
• live comments
• selected file / selected hunk
• maybe note visibility / other lightweight view state

A local-only sidecar under .hunk/ seems like a reasonable starting point.

Acceptance criteria

• A user can quit Hunk and later reopen the same review with comments restored.
• Restored sessions reconnect to the same review input, not just the same repo.
• Restoring a session also restores the current focus when possible.
• There is an explicit way to discard stale/old saved sessions.
• Add coverage for saving and restoring at least one live-comment session.

Notes

This issue is about persistence of review context, not only daemon uptime. Even if the daemon exits cleanly, users should still be able to resume a meaningful review later.