[BUG] Code tab opens detached scratch workspace after 1.46388.1 update, breaking project .claude/commands

Description

After a Claude Desktop app update to 1.46388.1 (auto-updated/relaunched ~2026-09-03 22:18 PT), new/reopened conversations in the Code tab are opening in a detached, anonymous "scratch workspace" instead of the project folder that was previously open/selected. This breaks any project-local .claude/commands/*.md custom slash command, since the session has no .claude directory to resolve them from.

Expected behavior

A Code tab conversation should open attached to the project folder the user was working in (or the one they explicitly select), so project-local .claude/commands/*.md files resolve normally via /<command-name>.

Actual behavior

• New conversations land in ~/Library/Application Support/Claude/scratch-workspaces/<account>/<session>/scratch-<date>/ with no project folder attached.
• The / autocomplete only surfaces items from the Skill catalog (SKILL.md-based skills) — it does not search .claude/commands/*.md at all, so a project command like /mem no longer even shows as a suggestion once the session has no project attached.
• This had been working continuously for the user for weeks before the update; nothing in the affected project's .claude/commands/mem.md file or its underlying CLI dependency changed in that window (last edits weeks prior), ruling out a project-side cause.

Environment

• Claude Desktop macOS, version 1.46388.1
• Update staged/relaunched: 2026-09-03 ~21:53–22:18 PT (from local config.json: updaterBannerStagedAt, version_first_launch)

Repro steps

1. Have a custom slash command installed at <project>/.claude/commands/foo.md, previously working via /foo in a Code tab conversation rooted in <project>.
2. Update Claude Desktop to 1.46388.1 (or start a fresh conversation after the update without explicitly picking a project folder).
3. Type /foo in the new conversation.

Result

/foo is absent from autocomplete (only Skill-catalog matches show), and the session's working directory is an unattached scratch workspace rather than <project>.