Filter and restore archived sidebar threads

[brsbl]

Human comments

What was wrong

Archived threads were absent from the sidebar hierarchy and could not be restored directly from their rows.

What changed

• Add Active and Archived checkboxes to the combined menu’s Filter submenu.
• Show archived rows in their existing sections, projects, machines, and pinned groups.
• Restore a thread through its persistent desktop Unarchive icon without navigating away; mobile rows hide that icon.
• Use background-only keyboard focus for sidebar action buttons; remove their outline rings.
• Sync the sidebar selection through existing SDK/CLI settings; document the preference.
• Load menu contents and the existing customization editor on demand to stay within the unchanged startup budget.

How you verified

• Exact-head CI passed all 13 jobs; PR merge-preview CI also passed.
• Chrome for Testing 153.0.8010.52: desktop archived rows render the shared ArchiveRestore glyph with the existing Unarchive label; mobile hides the row action. Refreshed 2× evidence below.
• Chrome for Testing 153.0.8010.52: Tab focus, Enter activation, and Escape restoration work without action-button rings.
• Shared button focus retains the existing background highlight. The rendered-header regression covers both primary and overflow controls.
• Prior-head filtering, last-choice protection, persistence, restore, cold menu/customization opening, keyboard selection, and compact Back verification passed.
• Current-head CI passed the unchanged startup budget.
• The inherited compact drawer focus/aria-hidden warning remains a separate follow-up.

Review and remaining gates

The completed cumulative Slop Cop review found no P0/P1 issues. No second review ran. Main integration removes the deferred saved-message search and draft-save guard changes.

P2 follow-ups remain separate: visible archived metadata can stay stale after remote edits; compact menu closure can leave focus on BODY. Native iOS Safari remains unverified. User QA is pending; nothing merged.

Screenshot evidence

Before: current main 699f2f1a8bfb0f22337ec30a0d5d53548baf56b9. After: 73692f4884d6fb8741b765c514c286b9b2bfb089. Same synthetic fixture, route, light theme, viewport, and 2× density. Main has no Filter submenu; those before images show its preceding combined menu. Archived-only/all comparisons show main’s active hierarchy with the same stored archived threads.

State	Viewport	Before	After
Combined menu	desktop · 1440×900	Open before	Open after
Filter · Active selected	desktop · 1440×900	Open before	Open after
Active and Archived · existing hierarchy	desktop · 1440×900	Open before	Open after
Archived only	desktop · 1440×900	Open before	Open after
Combined menu	mobile · 390×844	Open before	Open after
Filter · Active selected	mobile · 390×844	Open before	Open after
Active and Archived · existing hierarchy	mobile · 390×844	Open before	Open after
Archived only	mobile · 390×844	Open before	Open after

BB-Thread-ID: thr_cevdspix6j

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