feat(web): drag threads across sections with consistent motion

[juliusmarminge]

Only pinned threads previously had direct drag reordering. Threads can now move between Pinned, Active, and Settled, wake by dragging out of Snoozed, and keep the chosen position within Pinned or Active. Section hints appear during the drag without adding idle headers or moving the list at pickup.

A single sortable list keeps the dragged row and insertion gap continuous across section boundaries. Ordinary thread actions retain their section-change animations, including the card/compact fade, while drag completion avoids a second layout transition. Reduced-motion preferences are respected.

Older servers retain pinned reordering without settlement support. Drop planning reserves hidden order keys, and marker IDs cannot collide with scoped thread IDs.

Verified with 207 focused sidebar tests, web typecheck, targeted lint, and an integrated browser pass covering Active reordering, pin/unpin, and Settle/Un-settle. Recordings use disposable seeded threads. Web and desktop share this sidebar; mobile controls are in the preceding PR.

Before: dragging an Active thread	After: the row follows the insertion gap

Before: idle sidebar	After: idle sidebar, without Pinned or Active headings

Active reorder recordings: before, after.

Pinning and unpinning by drag:

https://gh-file-drop-api-prod-mi5fy3sowv63ufte.pinglabs.workers.dev/f/1caa2d3fcb56a1d0/web-cross-sections-final.mp4

Restored Settle and Un-settle animations:

https://gh-file-drop-api-prod-mi5fy3sowv63ufte.pinglabs.workers.dev/f/faabc7dac953ecb1/web-section-actions.mp4

Depends on #9730.

Prepared with Codex.

---

Note

Medium Risk
Large interaction surface touching pin/settle/snooze lifecycle and order-key persistence with optimistic concurrency, but logic is heavily unit-tested and gated on server capabilities.

Overview
Cross-section drag replaces pinned-only reordering: one DndContext and sortable list spans Pinned, Active, Settled, and Snoozed (wake on drag out; no drop into snooze). Section headers, dividers, and empty placeholders are sortable markers so the gap and drop targets stay continuous.

New Sidebar.drag and Sidebar.logic plumbing resolves destinations (resolveSidebarDropTarget), plans server writes (planSidebarThreadDrop — pin, unpin, settle, active reorder), and previews row state (applySidebarThreadDrop). Custom collision detection handles invalid targets and empty Pins; a custom sorting strategy projects layout across section boundaries (collapsed settled shelf, route row visibility, etc.).

Motion and animation: @formkit/auto-animate is removed in favor of Sidebar.motion for post-action section moves (with reduced-motion and drag suspend). animateSidebarLayoutChanges avoids double animation after drop. Active list order now follows activeOrderKey via shared client-runtime sort helpers; drops call reorderActiveThread when the server exposes threadActiveReorder.

Optimistic optimisticDrop generalizes the old pinned-order hold across section moves and key writes until canonical state catches up. UI shows drag destination hints and boundary labels only while dragging.

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Note

Add cross-section thread dragging with consistent motion to sidebar

• Adds dragging threads between Pinned, Active, Snoozed, and Settled sections. The drop planner generates lifecycle commands, and an optimistic projector previews the thread in its destination before server confirmation.
• Introduces createSidebarListMotion in Sidebar.motion.ts to animate retained rows with 150ms ease-out translations, fade entering and exiting rows, and honor reduced-motion preferences.
• Replaces pinned-only DnD utilities with a unified sortable list in Sidebar.tsx spanning all sections, including structural markers and empty-section placeholders as drop targets.
• Risk: sortThreadsForSidebar now uses the client-runtime Active order-key sorter instead of the previous timestamp-and-id comparator, and activeThreadAnchorTimestampMs is removed from the threadSort re-export surface.

^{Macroscope summarized 33e70c4.}

[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

ℹ️ No successful main baseline artifact is available yet. This run establishes the initial measurement.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	—	13.6 KiB	—	15.1 KiB	✅
Codex	Thread snapshot wire	—	7.0 KiB	—	7.3 KiB	✅
Codex	Live turn WebSocket wire	—	6.6 KiB	—	7.8 KiB	✅
Codex	Live turn WebSocket decoded	—	57.1 KiB	—	66.4 KiB	✅
Codex	Live turn messages	—	10	—	21	✅
Claude	Total thread wire	—	13.6 KiB	—	15.1 KiB	✅
Claude	Thread snapshot wire	—	7.0 KiB	—	7.3 KiB	✅
Claude	Live turn WebSocket wire	—	6.5 KiB	—	7.8 KiB	✅
Claude	Live turn WebSocket decoded	—	57.8 KiB	—	66.4 KiB	✅
Claude	Live turn messages	—	9	—	21	✅

Baseline: unavailable · PR result: e908032 · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 113.9 KiB
• Claude decoded thread snapshot: 114.6 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.

[macroscopeapp]

Approvability

Verdict: Not approved

Macroscope's review found this PR not approvable — This PR adds cross-section drag-and-drop with persistent reordering and lifecycle mutations, while replacing the sidebar's drag and animation architecture. Because it changes existing ordering behavior and can issue multiple state-changing server commands, the scope and runtime impact require human review.

Not approved because:

• Monthly spending limit reached (workspace setting). Approvability relies on correctness review in order to determine eligibility

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