Todo Panel — Create items per category + WebSocket sync #47

Parent

#44

What to build

A per-category inline composer for creating new todo items, plus the WebSocket mutation API to persist them. Items render within their category section, sorted by creation time (newest last).

State machine: todoStore gains createItem(categoryId, title) — creates a new item with status todo, assigns an order, generates an ID, sets createdAt.

WebSocket: todo.mutate NativeApi method accepts a mutation and returns the updated state. Batched mutations so future slices (drag) can commit atomically.

UI: Each category header has a "+" icon button inline. Clicking it reveals a small text input. Pressing Enter creates the item with the entered title. Items appear below the category header in creation-time order.

Tests: todoStore — item creation, ordering. todoPersistence — items survive restart.

Acceptance criteria

• todoStore.createItem(categoryId, title) creates item with correct defaults (status=todo, order, id, createdAt)
• todo.mutate WebSocket method accepts mutation payload and returns updated state
• Server persists mutations to ~/.t3code/todos.json via debounced atomic write
• "+" icon button inline with each category header
• Clicking "+" reveals a text input; Enter creates the item; Escape cancels
• Items render sorted by createdAt within their category
• Items render with title and status icon (static for now, no click-to-cycle yet)
• Unit tests: createItem assigns correct defaults, ordering
• bun fmt, bun lint, bun typecheck all pass

Blocked by

• Todo Panel — Read-only categories from JSON persistence #46