[BUG] Sessions repeatedly auto-archived during active use, no way to unarchive

What happened

Three Claude Code sessions in a row got auto-archived during active use, with no way to unarchive them afterward (no unarchive control / no Archived view surfaced).

This matches the pattern already reported in #57602, #68972, and #59449 — but those were auto-closed as duplicates and are now locked, so I can't comment or react on them. Filing fresh since the underlying bug is still live and recurring (3x for me specifically, not a one-off).

Repro / pattern observed

• Happened 3 separate times across recent sessions, each ending the conversation mid-task
• No Stop / SessionStart / archive hooks configured in local settings.json or settings.local.json — ruled out local config as the cause
• No scheduled tasks or keybindings that reference archiving
• Each time, the session became inaccessible with no in-app way to restore it

Expected

An active (non-idle) session should not be auto-archived, and regardless, there should be a way to unarchive a session that was archived unexpectedly (tracked separately in #67835, still open).

Related

• #57602 (closed/locked duplicate root — Windows focus-loss trigger)
• #68972 (closed/locked duplicate — archive immediately after response)
• #59449 (closed/locked duplicate — archive every ~5 min during normal interaction)
• #67835 (open — no unarchive tool / no Archived view)

Session transcripts are still on disk under ~/.claude/projects/<project>/<session-id>.jsonl even when archived, so no data is lost — just inaccessible via the UI.