feat(web): let the sidebar's sections be arranged by hand

[BarretoDiego]

Problem

Section order in the sidebar was whatever the grouping produced: sections with live work first, then history-only ones, then quiet seeded projects, with first-appearance breaking ties. A good default, a poor permanent arrangement — the project you check every morning drifts down the list the moment nothing is running in it, and environments had no ordering control at all.

What changed

Ordering is now a second pass over the built section tree, kept separate from grouping. Three modes, in the menu that already sorts threads:

• Busiest first — the previous behavior, still the default.
• Name (A–Z).
• Custom (drag to arrange).

Custom is reachable two ways: drag a section header, or right-click it and pick Move up / Move down. Either one switches to Custom and records the whole level, so the result stops depending on activity. Reset section order goes back to Busiest first.

Sections move only within their own level. A drop outside the dragged section's siblings is refused, and while a drag is in flight every other level disables its droppables, so a project level never animates a swap it would discard. Sections cannot be reparented, only resequenced.

Notes on the design

• Header rows now carry their parent, siblings and index, so a reorder never has to recover the level by splitting keys on /.
• The manual list is one flat array across levels — child keys are already parent-prefixed. Keys of sections that are not currently rendered are kept rather than pruned, because grouping axes and the provider filter hide sections temporarily.
• Switching to Custom from the menu seeds every unplaced section where it currently sits, freezing the layout on screen. A project added later joins the end of its level.

Verification

• vp test run apps/web/src/components/sidebarThreadGrouping.test.ts — 42 passed, including new coverage for orderSidebarThreadGroups, planSidebarSectionOrder, collectSidebarSectionKeys and the level facts on header rows.
• vp test run on Sidebar.logic, Sidebar.snooze, environmentGrouping, CommandPalette.logic, ui/sidebar, SidebarStageBackdrop, threadSidebarWidth, DesktopClientSettings — all passing.
• tsgo --noEmit clean for apps/web, apps/desktop, packages/contracts; vp lint clean for the touched files.
• No browser pass — say the word and I will drive the real app for before/after shots of the drag.

Written by Claude Opus 5 in Claude Code.

🤖 Generated with Claude Code