[jsgrrchg]

Summary

Custom sidebar sections can now be reordered by dragging their header on desktop. The order syncs across devices like pins and section members do. Until now, sections always showed in creation order.

Data and sync

• SidebarSectionChange::Move { id, after, before } places a section between its neighbours, using the same anchor rule as Assign (section_insert_index). Its project() reorders the local Vec, which covers the optimistic queue and Local workspaces.
• Each sidebarSections row gets its own orderKey, minted with pin_order_key_between between the neighbours' keys. Concurrent moves of one section converge by clock, and moves of different sections both survive.
• Ordering: keyed sections by (orderKey, id), then unkeyed ones by (createdAt, id). Until the first move, nothing changes. Sections created later, including by older apps or iOS, append.
• The first move keys every unkeyed section in its current order. This reuses the member-placement logic, now factored into place_among and shared by members and sections.
• No edge change: sidebarSections has no field allow-list.

Compatibility

• New capability sidebar-section-order-v1. An older engine would reject the unknown action, so the UI only offers the drag in Local scope, or in synced scope when the engine advertises it.
• Apps that predate this ignore orderKey and keep showing creation order. They lose nothing: their renames and collapses don't touch the key.
• Mobile gets no reorder UI. A rebuilt iOS app picks up the order automatically through zeron-doc.

Desktop UI

• Dragging a section header lifts the whole section, frosted like a lifted session, while its siblings slide aside (TAB_SLIDE). The section lands past a sibling once its leading edge crosses that sibling's middle, so sections of different heights reorder naturally.
• The list edge-scrolls during the drag. Releasing outside the sidebar settles the section back home, and drops and cancels glide through the existing resort animation. Reduced motion is respected.
• Header clicks still collapse and expand.

iOS: drag sessions between sections

• Long-press a session on the front page and drag it into Pinned or a user section at the slot it's dropped on, or back to Recent. Placements carry after/before anchors, so the order syncs with desktop. A folded destination opens to show the row.
• Sections now list their members in their placed order, as desktop does, instead of by recency.
• Client/FFI: pin_session_at and place_session; assign_section places without anchors. zeron_core.swift regenerated.
• Reordering sections themselves stays desktop-only.
• Tests: sidebar_writes_reorder_the_front_page (client demo) covers anchored placement, unpinning on placement and anchored pins.

Tests

• section_move_reorders_sections_by_anchor (proto)
• sidebar_sections_reorder_and_converge_across_devices (doc): unmoved order, appended unkeyed sections, concurrent moves of different sections and of the same section, deleted sections and anchors
• sections_reorder_by_dragging_their_header (ui): real mouse drag, plus a release outside the sidebar
• section_drop_index_follows_the_leading_edge (ui)

docs/registry-sync.md describes section ordering.

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[wingleeio]

Security audit: clean — hostile/oversized orderKey values fall back to creation order, anchors are validated, no unwraps on synced data, FFI is plain String passthrough, regenerated Swift matches uniffi output, capability gate is correct.

Pushed one fix (e7ad957): placing a section re-keyed every section once any lacked a key, so after a section was created, the next move could overwrite a concurrent move from another device with a later clock. Now only the keyless tail is keyed (past the last key), with a full re-key only when no key fits. Added a regression case to sidebar_sections_reorder_and_converge_across_devices, de-flaked its same-section concurrent step, and deduped section members in the client view. Thanks!