Why: creation entries were split (project + at sidebar top-left, new
session at bottom-left) and the project tree forced per-project
navigation; the approved option A design makes one primary New Task
entry, organization a view mode, and identity always present.
Evidence:
- New TaskSidebar: single New Task split button (current-project context,
Cmd-N, secondary menu for new project / new task in project), project
<-> timeline organization with persisted collapse, pinned section,
archive view toggle, hover row actions, account footer fed by
/api/me (embedded mode shows local tenant; logout clears the key),
workspace icon strip retained (D25 shared list with Cmd-1..9).
- store: tasks = cross-project list via GET /api/conversations; openTask
switches project context; pin/archive optimistic + refresh; last
project context persisted; stale conversations field removed.
- tasklist.ts pure helpers + 6 vitest cases; npm run build passes;
headless walk on the real binary: cross-project open, pinned-first,
archive hide/show/restore, new-task flow, zero console errors.
Impact: ProjectNav removed; contracts.ts regenerated from core
(pinned/archived); no composer/right-pane changes (D25/D26/D31 intact).
Refs: Agent-System-Documents docs/proposals/2026-09-30-ui-redesign-and-auth.md
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