[Desktop] Bring back the sidebar status filter (show archived sessions in the sidebar)

Related: #102116 (same regression). Filing separately to add the workflow impact and the missing feedback route.

What changed

The Code tab sidebar's filter menu used to have a status filter (Active / Archived / All), so archived sessions could optionally be shown right in the sidebar. After the update to the sections layout, the menu only offers Group by / Sort by / Show / New section / Reset to defaults / View all. Archived sessions can only be reached through the separate "View all" page.

Why it matters

I archive every PR review session once the review is posted. When the author pushes fixes, I used to toggle archived sessions on in the sidebar, reopen the review session, and continue with its full context. That was one click. Now it's a detour to a separate page, many times a day, so archiving stops being a safe, instant-to-undo way to keep the sidebar clean.

Also: no working feedback route

• /feedback in the terminal only saved a local bundle (~/.claude/feedback-bundles/*.zip) and didn't send anything.
• I couldn't find a "Send feedback" entry in the desktop app's Help menu.

GitHub was the only way I found to report this.

Requested

Restore the Active / Archived / All status filter in the sidebar filter menu (or add a "Show archived" toggle under Show), so archived sessions can be shown in place without leaving the sidebar.

Environment: Windows 11, Claude desktop app, Code tab.