Todo Panel — Schema + empty sidebar shell with cmd+L toggle #45

Parent

#44

What to build

Define the shared TypeScript types in packages/contracts and stand up an empty right sidebar shell in the web app.

The sidebar must match the existing diff sidebar pattern: SidebarProvider + Sidebar with side="right", collapsible="offcanvas", resizable, controlled by local state. Toggled via cmd+L keybinding, registered through the existing command system.

At this stage the sidebar renders empty (no data, no items, no categories). Its sole purpose is to prove the shell opens/closes correctly and matches the diff sidebar's look and feel.

Acceptance criteria

• cmd+L toggles a right sidebar open and closed
• Sidebar uses the existing shadcn Sidebar pattern (SidebarProvider, Sidebar with side="right")
• Sidebar is resizable and collapsible (offcanvas mode)
• Keybinding is registered through the existing command registration system (same pattern as diff sidebar)
• Types for TodoCategory and TodoItem are defined in packages/contracts (no runtime logic yet)
• bun fmt, bun lint, bun typecheck all pass

Blocked by

None — can start immediately.