The selected tab was a single, non-workstream-scoped value that a clamp effect reset to the first tab on every workstream switch, so returning to a workstream always lost the last-used tab. - Scope the selected tab per workstream (activeTabByNode) and persist it to KV (activeTab); seed it back when a workstream opens, so the last-used tab is restored across switches and reloads. - Drag tabs to reorder (native HTML5 DnD), persisting the order to KV (tabOrder) and applying it via a pure, tested helper (tabOrder.ts) with local drag optimism; new tabs sort to the end. - Carry tabOrder/activeTab through the store and the reconcile loop. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01983EhvGRpnNpiKRcvPcCvk